135516629427921 has 81 divisors (see below), whose sum is σ = 228392450115921. Its totient is φ = 77204924786304.

The previous prime is 135516629427871. The next prime is 135516629428027. The reversal of 135516629427921 is 129724926615531.

The square root of 135516629427921 is 11641161.

It is a perfect power (a square), and thus also a powerful number.

135516629427921 is a `hidden beast` number, since 1 + 3 + 5 + 5 + 166 + 29 + 427 + 9 + 21 = 666.

135516629427921 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 4018577520321 + 131498051907600 = 2004639^2 + 11467260^2 .

It is not a de Polignac number, because 135516629427921 - 2⁹ = 135516629427409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

Its product of digits (48988800) is a multiple of the sum of its prime divisors (1680).

It is not an unprimeable number, because it can be changed into a prime (135516629422921) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 111720221511 + ... + 111720222723.

Almost surely, 2^{135516629427921} is an apocalyptic number.

135516629427921 is the 11641161-st square number.

135516629427921 is the 5820581-st centered octagonal number.

It is an amenable number.

135516629427921 is a deficient number, since it is larger than the sum of its proper divisors (92875820688000).

135516629427921 is an frugal number, since it uses more digits than its factorization.

135516629427921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3360 (or 1680 counting only the distinct ones).

The product of its digits is 48988800, while the sum is 63.

The spelling of 135516629427921 in words is "one hundred thirty-five trillion, five hundred sixteen billion, six hundred twenty-nine million, four hundred twenty-seven thousand, nine hundred twenty-one".