20854536921 has 27 divisors (see below), whose sum is σ = 30983179773. Its totient is φ = 13516869600.

The previous prime is 20854536919. The next prime is 20854536961. The reversal of 20854536921 is 12963545802.

The square root of 20854536921 is 144411.

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

20854536921 is a `hidden beast` number, since 20 + 8 + 5 + 4 + 536 + 92 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1717688025 + 19136848896 = 41445^2 + 138336^2 .

It is not a de Polignac number, because 20854536921 - 2¹ = 20854536919 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20854536961) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 16028971 + ... + 16030271.

Almost surely, 2^20854536921 is an apocalyptic number.

20854536921 is the 144411-st square number.

20854536921 is the 72206-th centered octagonal number.

It is an amenable number.

20854536921 is a deficient number, since it is larger than the sum of its proper divisors (10128642852).

20854536921 is an frugal number, since it uses more digits than its factorization.

20854536921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2682 (or 1341 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 20854536921 in words is "twenty billion, eight hundred fifty-four million, five hundred thirty-six thousand, nine hundred twenty-one".