20645055021 has 16 divisors (see below), whose sum is σ = 28623504960. Its totient is φ = 13219906560.

The previous prime is 20645054971. The next prime is 20645055031. The reversal of 20645055021 is 12055054602.

It is not a de Polignac number, because 20645055021 - 2⁷ = 20645054893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20645055021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645055031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 597975 + ... + 631556.

It is an arithmetic number, because the mean of its divisors is an integer number (1788969060).

Almost surely, 2^20645055021 is an apocalyptic number.

It is an amenable number.

20645055021 is a deficient number, since it is larger than the sum of its proper divisors (7978449939).

20645055021 is a wasteful number, since it uses less digits than its factorization.

20645055021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1229756.

The product of its (nonzero) digits is 12000, while the sum is 30.

The spelling of 20645055021 in words is "twenty billion, six hundred forty-five million, fifty-five thousand, twenty-one".