27921407409 has 81 divisors (see below), whose sum is σ = 48007443393. Its totient is φ = 15592155264.

The previous prime is 27921407407. The next prime is 27921407429. The reversal of 27921407409 is 90470412972.

It is a happy number.

The square root of 27921407409 is 167097.

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

27921407409 is a `hidden beast` number, since 27 + 9 + 214 + 0 + 7 + 409 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1991390625 + 25930016784 = 44625^2 + 161028^2 .

It is not a de Polignac number, because 27921407409 - 2¹ = 27921407407 is a prime.

It is not an unprimeable number, because it can be changed into a prime (27921407407) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 256159647 + ... + 256159755.

Almost surely, 2^27921407409 is an apocalyptic number.

27921407409 is the 167097-th square number.

27921407409 is the 83549-th centered octagonal number.

It is an amenable number.

27921407409 is a deficient number, since it is larger than the sum of its proper divisors (20086035984).

27921407409 is an equidigital number, since it uses as much as digits as its factorization.

27921407409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The spelling of 27921407409 in words is "twenty-seven billion, nine hundred twenty-one million, four hundred seven thousand, four hundred nine".