21720355038516 has 24 divisors (see below), whose sum is σ = 50728505619904. Its totient is φ = 7233307318080.

The previous prime is 21720355038509. The next prime is 21720355038523. The reversal of 21720355038516 is 61583055302712.

It is an interprime number because it is at equal distance from previous prime (21720355038509) and next prime (21720355038523).

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, 851365225 + ... + 851390736.

Almost surely, 2^{21720355038516} is an apocalyptic number.

It is an amenable number.

21720355038516 is an abundant number, since it is smaller than the sum of its proper divisors (29008150581388).

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

21720355038516 is a wasteful number, since it uses less digits than its factorization.

21720355038516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1702757031 (or 1702757029 counting only the distinct ones).

The product of its (nonzero) digits is 1512000, while the sum is 48.

The spelling of 21720355038516 in words is "twenty-one trillion, seven hundred twenty billion, three hundred fifty-five million, thirty-eight thousand, five hundred sixteen".