21121141551655 has 16 divisors (see below), whose sum is σ = 25535668384800. Its totient is φ = 16770123348480.

The previous prime is 21121141551649. The next prime is 21121141551659. The reversal of 21121141551655 is 55615514112112.

It is not a de Polignac number, because 21121141551655 - 2³ = 21121141551647 is a prime.

It is a super-2 number, since 2×21121141551655² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121141551659) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2504886 + ... + 6965395.

It is an arithmetic number, because the mean of its divisors is an integer number (1595979274050).

Almost surely, 2^{21121141551655} is an apocalyptic number.

21121141551655 is a deficient number, since it is larger than the sum of its proper divisors (4414526833145).

21121141551655 is a wasteful number, since it uses less digits than its factorization.

21121141551655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9473634.

The product of its digits is 60000, while the sum is 40.

Adding to 21121141551655 its reverse (55615514112112), we get a palindrome (76736655663767).

The spelling of 21121141551655 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred forty-one million, five hundred fifty-one thousand, six hundred fifty-five".