21054615720 has 32 divisors (see below), whose sum is σ = 63163847520. Its totient is φ = 5614564160.

The previous prime is 21054615707. The next prime is 21054615737. The reversal of 21054615720 is 2751645012.

It is a super-2 number, since 2×21054615720² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87727446 + ... + 87727685.

It is an arithmetic number, because the mean of its divisors is an integer number (1973870235).

Almost surely, 2^21054615720 is an apocalyptic number.

21054615720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21054615720 is an abundant number, since it is smaller than the sum of its proper divisors (42109231800).

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

21054615720 is a wasteful number, since it uses less digits than its factorization.

21054615720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175455145 (or 175455141 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 33.

The spelling of 21054615720 in words is "twenty-one billion, fifty-four million, six hundred fifteen thousand, seven hundred twenty".