20646092921 has 4 divisors (see below), whose sum is σ = 20699168100. Its totient is φ = 20593017744.

The previous prime is 20646092903. The next prime is 20646092939. The reversal of 20646092921 is 12929064602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20646092903) and next prime (20646092939).

It can be written as a sum of positive squares in 2 ways, for example, as 8734771600 + 11911321321 = 93460^2 + 109139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20646092921 - 2²⁶ = 20578984057 is a prime.

It is a super-2 number, since 2×20646092921² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20646092941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26537006 + ... + 26537783.

It is an arithmetic number, because the mean of its divisors is an integer number (5174792025).

Almost surely, 2^20646092921 is an apocalyptic number.

It is an amenable number.

20646092921 is a deficient number, since it is larger than the sum of its proper divisors (53075179).

20646092921 is an equidigital number, since it uses as much as digits as its factorization.

20646092921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53075178.

The product of its (nonzero) digits is 93312, while the sum is 41.

The spelling of 20646092921 in words is "twenty billion, six hundred forty-six million, ninety-two thousand, nine hundred twenty-one".