21671516540 has 24 divisors (see below), whose sum is σ = 45514271040. Its totient is φ = 8667828288.

The previous prime is 21671516533. The next prime is 21671516593. The reversal of 21671516540 is 4561517612.

It is a junction number, because it is equal to n+sod(n) for n = 21671516494 and 21671516503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214349 + ... + 298811.

It is an arithmetic number, because the mean of its divisors is an integer number (1896427960).

Almost surely, 2^21671516540 is an apocalyptic number.

21671516540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21671516540 is an abundant number, since it is smaller than the sum of its proper divisors (23842754500).

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

21671516540 is a wasteful number, since it uses less digits than its factorization.

21671516540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97301 (or 97299 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 38.

The spelling of 21671516540 in words is "twenty-one billion, six hundred seventy-one million, five hundred sixteen thousand, five hundred forty".