20320637221 has 4 divisors (see below), whose sum is σ = 20322262444. Its totient is φ = 20319012000.

The previous prime is 20320637191. The next prime is 20320637257. The reversal of 20320637221 is 12273602302.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14030402500 + 6290234721 = 118450^2 + 79311^2 .

It is a cyclic number.

It is not a de Polignac number, because 20320637221 - 2¹⁵ = 20320604453 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20320637221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20320637291) 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, 793710 + ... + 818911.

It is an arithmetic number, because the mean of its divisors is an integer number (5080565611).

Almost surely, 2^20320637221 is an apocalyptic number.

It is an amenable number.

20320637221 is a deficient number, since it is larger than the sum of its proper divisors (1625223).

20320637221 is a wasteful number, since it uses less digits than its factorization.

20320637221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1625222.

The product of its (nonzero) digits is 6048, while the sum is 28.

The spelling of 20320637221 in words is "twenty billion, three hundred twenty million, six hundred thirty-seven thousand, two hundred twenty-one".