21515440452 has 48 divisors (see below), whose sum is σ = 55007914752. Its totient is φ = 6491099680.

The previous prime is 21515440439. The next prime is 21515440493. The reversal of 21515440452 is 25404451512.

It is a happy number.

It is a super-3 number, since 3×21515440452³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 329058 + ... + 388985.

It is an arithmetic number, because the mean of its divisors is an integer number (1145998224).

Almost surely, 2^21515440452 is an apocalyptic number.

21515440452 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21515440452 is an abundant number, since it is smaller than the sum of its proper divisors (33492474300).

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

21515440452 is a wasteful number, since it uses less digits than its factorization.

21515440452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718288 (or 718286 counting only the distinct ones).

The product of its (nonzero) digits is 32000, while the sum is 33.

Adding to 21515440452 its reverse (25404451512), we get a palindrome (46919891964).

The spelling of 21515440452 in words is "twenty-one billion, five hundred fifteen million, four hundred forty thousand, four hundred fifty-two".