20307706621 has 4 divisors (see below), whose sum is σ = 20779978912. Its totient is φ = 19835434332.

The previous prime is 20307706613. The next prime is 20307706667. The reversal of 20307706621 is 12660770302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20307706621 - 2³ = 20307706613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20307706421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236136081 + ... + 236136166.

It is an arithmetic number, because the mean of its divisors is an integer number (5194994728).

Almost surely, 2^20307706621 is an apocalyptic number.

It is an amenable number.

20307706621 is a deficient number, since it is larger than the sum of its proper divisors (472272291).

20307706621 is an equidigital number, since it uses as much as digits as its factorization.

20307706621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472272290.

The product of its (nonzero) digits is 21168, while the sum is 34.

The spelling of 20307706621 in words is "twenty billion, three hundred seven million, seven hundred six thousand, six hundred twenty-one".