21720072731516 has 12 divisors (see below), whose sum is σ = 40246017120288. Its totient is φ = 10221210697152.

The previous prime is 21720072731507. The next prime is 21720072731531. The reversal of 21720072731516 is 61513727002712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159706417076 + ... + 159706417211.

It is an arithmetic number, because the mean of its divisors is an integer number (3353834760024).

Almost surely, 2^{21720072731516} is an apocalyptic number.

It is an amenable number.

21720072731516 is a deficient number, since it is larger than the sum of its proper divisors (18525944388772).

21720072731516 is a wasteful number, since it uses less digits than its factorization.

21720072731516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319412834308 (or 319412834306 counting only the distinct ones).

The product of its (nonzero) digits is 246960, while the sum is 44.

The spelling of 21720072731516 in words is "twenty-one trillion, seven hundred twenty billion, seventy-two million, seven hundred thirty-one thousand, five hundred sixteen".