21513123416 has 128 divisors (see below), whose sum is σ = 46111887360. Its totient is φ = 9351936000.

The previous prime is 21513123409. The next prime is 21513123419. The reversal of 21513123416 is 61432131512.

It is a super-2 number, since 2×21513123416² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513123419) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17475521 + ... + 17476751.

It is an arithmetic number, because the mean of its divisors is an integer number (360249120).

Almost surely, 2^21513123416 is an apocalyptic number.

It is an amenable number.

21513123416 is an abundant number, since it is smaller than the sum of its proper divisors (24598763944).

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

21513123416 is a wasteful number, since it uses less digits than its factorization.

21513123416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465 (or 1461 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

Adding to 21513123416 its reverse (61432131512), we get a palindrome (82945254928).

The spelling of 21513123416 in words is "twenty-one billion, five hundred thirteen million, one hundred twenty-three thousand, four hundred sixteen".