21154521023216 has 40 divisors (see below), whose sum is σ = 46842691027680. Its totient is φ = 9066119295744.

The previous prime is 21154521023179. The next prime is 21154521023227. The reversal of 21154521023216 is 61232012545112.

It is a super-2 number, since 2×21154521023216² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9153830 + ... + 11229498.

It is an arithmetic number, because the mean of its divisors is an integer number (1171067275692).

Almost surely, 2^{21154521023216} is an apocalyptic number.

It is an amenable number.

21154521023216 is an abundant number, since it is smaller than the sum of its proper divisors (25688170004464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21154521023216 is a wasteful number, since it uses less digits than its factorization.

21154521023216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2166681 (or 2166675 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

Adding to 21154521023216 its reverse (61232012545112), we get a palindrome (82386533568328).

The spelling of 21154521023216 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred twenty-one million, twenty-three thousand, two hundred sixteen".