20947922645 has 30 divisors (see below), whose sum is σ = 27303514158. Its totient is φ = 15428845536.

The previous prime is 20947922603. The next prime is 20947922647. The reversal of 20947922645 is 54622974902.

It can be written as a sum of positive squares in 5 ways, for example, as 18800248996 + 2147673649 = 137114^2 + 46343^2 .

It is not a de Polignac number, because 20947922645 - 2¹² = 20947918549 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20947922593 and 20947922602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20947922647) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 54694124 + ... + 54694506.

Almost surely, 2^20947922645 is an apocalyptic number.

It is an amenable number.

20947922645 is a deficient number, since it is larger than the sum of its proper divisors (6355591513).

20947922645 is an frugal number, since it uses more digits than its factorization.

20947922645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 823 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 50.

The spelling of 20947922645 in words is "twenty billion, nine hundred forty-seven million, nine hundred twenty-two thousand, six hundred forty-five".