21477351720 has 64 divisors (see below), whose sum is σ = 70289519040. Its totient is φ = 5206630400.

The previous prime is 21477351719. The next prime is 21477351733. The reversal of 21477351720 is 2715377412.

It is a super-2 number, since 2×21477351720² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8134041 + ... + 8136680.

It is an arithmetic number, because the mean of its divisors is an integer number (1098273735).

Almost surely, 2^21477351720 is an apocalyptic number.

21477351720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21477351720 is an abundant number, since it is smaller than the sum of its proper divisors (48812167320).

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

21477351720 is a wasteful number, since it uses less digits than its factorization.

21477351720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16270746 (or 16270742 counting only the distinct ones).

The product of its (nonzero) digits is 82320, while the sum is 39.

The spelling of 21477351720 in words is "twenty-one billion, four hundred seventy-seven million, three hundred fifty-one thousand, seven hundred twenty".