21992593401 has 9 divisors (see below), whose sum is σ = 31767721999. Its totient is φ = 14661432336.

The previous prime is 21992593391. The next prime is 21992593411. The reversal of 21992593401 is 10439529912.

The square root of 21992593401 is 148299.

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

21992593401 is a `hidden beast` number, since 2 + 19 + 9 + 2 + 593 + 40 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (21992593391) and next prime (21992593411).

It can be written as a sum of positive squares in only one way, i.e., 14729463225 + 7263130176 = 121365^2 + 85224^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21992593401 - 2⁵ = 21992593369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21992593411) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 420181 + ... + 469613.

Almost surely, 2^21992593401 is an apocalyptic number.

21992593401 is the 148299-th square number.

21992593401 is the 74150-th centered octagonal number.

It is an amenable number.

21992593401 is a deficient number, since it is larger than the sum of its proper divisors (9775128598).

21992593401 is an frugal number, since it uses more digits than its factorization.

21992593401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98872 (or 49436 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 45.

The spelling of 21992593401 in words is "twenty-one billion, nine hundred ninety-two million, five hundred ninety-three thousand, four hundred one".