20505851597 has 12 divisors (see below), whose sum is σ = 25567303776. Its totient is φ = 15977606520.

The previous prime is 20505851591. The next prime is 20505851623. The reversal of 20505851597 is 79515850502.

It is not a de Polignac number, because 20505851597 - 2¹⁶ = 20505786061 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20505851591) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1248404 + ... + 1264722.

It is an arithmetic number, because the mean of its divisors is an integer number (2130608648).

Almost surely, 2^20505851597 is an apocalyptic number.

It is an amenable number.

20505851597 is a deficient number, since it is larger than the sum of its proper divisors (5061452179).

20505851597 is an frugal number, since it uses more digits than its factorization.

20505851597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32656 (or 16337 counting only the distinct ones).

The product of its (nonzero) digits is 630000, while the sum is 47.

The spelling of 20505851597 in words is "twenty billion, five hundred five million, eight hundred fifty-one thousand, five hundred ninety-seven".