21206057513471 has 8 divisors (see below), whose sum is σ = 21866487133680. Its totient is φ = 20555269201792.

The previous prime is 21206057513383. The next prime is 21206057513489. The reversal of 21206057513471 is 17431575060212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21206057513471 is a prime.

It is a super-3 number, since 3×21206057513471³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206057513071) 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, 2410322666 + ... + 2410331463.

It is an arithmetic number, because the mean of its divisors is an integer number (2733310891710).

Almost surely, 2^{21206057513471} is an apocalyptic number.

21206057513471 is a deficient number, since it is larger than the sum of its proper divisors (660429620209).

21206057513471 is an equidigital number, since it uses as much as digits as its factorization.

21206057513471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4820654265.

The product of its (nonzero) digits is 352800, while the sum is 44.

The spelling of 21206057513471 in words is "twenty-one trillion, two hundred six billion, fifty-seven million, five hundred thirteen thousand, four hundred seventy-one".