216434556133551 has 128 divisors (see below), whose sum is σ = 374911952486400. Its totient is φ = 120830520769920.

The previous prime is 216434556133529. The next prime is 216434556133597. The reversal of 216434556133551 is 155331655434612.

216434556133551 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 3 + 4 + 5 + 56 + 1 + 33 + 551 = 666.

216434556133551 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 216434556133551 - 2⁹ = 216434556133039 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216434556333551) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 14833421266 + ... + 14833435856.

It is an arithmetic number, because the mean of its divisors is an integer number (2928999628800).

Almost surely, 2^{216434556133551} is an apocalyptic number.

216434556133551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

216434556133551 is a deficient number, since it is larger than the sum of its proper divisors (158477396352849).

216434556133551 is a wasteful number, since it uses less digits than its factorization.

216434556133551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17506 (or 17500 counting only the distinct ones).

The product of its digits is 19440000, while the sum is 54.

The spelling of 216434556133551 in words is "two hundred sixteen trillion, four hundred thirty-four billion, five hundred fifty-six million, one hundred thirty-three thousand, five hundred fifty-one".