21857457638416 has 15 divisors (see below), whose sum is σ = 42348860407231. Its totient is φ = 10928719468816.

The previous prime is 21857457638399. The next prime is 21857457638479. The reversal of 21857457638416 is 61483675475812.

The square root of 21857457638416 is 4675196.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 18116385 + ... + 19285183.

Almost surely, 2^{21857457638416} is an apocalyptic number.

21857457638416 is the 4675196-th square number.

It is an amenable number.

21857457638416 is a deficient number, since it is larger than the sum of its proper divisors (20491402768815).

21857457638416 is an frugal number, since it uses more digits than its factorization.

21857457638416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2337606 (or 1168801 counting only the distinct ones).

The product of its digits is 270950400, while the sum is 67.

The spelling of 21857457638416 in words is "twenty-one trillion, eight hundred fifty-seven billion, four hundred fifty-seven million, six hundred thirty-eight thousand, four hundred sixteen".