20522645621 has 4 divisors (see below), whose sum is σ = 20672446092. Its totient is φ = 20372845152.

The previous prime is 20522645569. The next prime is 20522645639. The reversal of 20522645621 is 12654622502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12654622502 = 2 ⋅6327311251.

It can be written as a sum of positive squares in 2 ways, for example, as 4013222500 + 16509423121 = 63350^2 + 128489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20522645621 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 (20522645681) 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, 74900030 + ... + 74900303.

It is an arithmetic number, because the mean of its divisors is an integer number (5168111523).

Almost surely, 2^20522645621 is an apocalyptic number.

It is an amenable number.

20522645621 is a deficient number, since it is larger than the sum of its proper divisors (149800471).

20522645621 is a wasteful number, since it uses less digits than its factorization.

20522645621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149800470.

The product of its (nonzero) digits is 57600, while the sum is 35.

The spelling of 20522645621 in words is "twenty billion, five hundred twenty-two million, six hundred forty-five thousand, six hundred twenty-one".