15516215156721 has 8 divisors (see below), whose sum is σ = 21169409826400. Its totient is φ = 10103581962432.

The previous prime is 15516215156711. The next prime is 15516215156789. The reversal of 15516215156721 is 12765151261551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15516215156721 - 2²³ = 15516206768113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15516215156711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60140368696 + ... + 60140368953.

It is an arithmetic number, because the mean of its divisors is an integer number (2646176228300).

Almost surely, 2^{15516215156721} is an apocalyptic number.

It is an amenable number.

15516215156721 is a deficient number, since it is larger than the sum of its proper divisors (5653194669679).

15516215156721 is a wasteful number, since it uses less digits than its factorization.

15516215156721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120280737695.

The product of its digits is 630000, while the sum is 48.

The spelling of 15516215156721 in words is "fifteen trillion, five hundred sixteen billion, two hundred fifteen million, one hundred fifty-six thousand, seven hundred twenty-one".