20686772737 has 4 divisors (see below), whose sum is σ = 20690109616. Its totient is φ = 20683435860.

The previous prime is 20686772699. The next prime is 20686772741. The reversal of 20686772737 is 73727768602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 73727768602 = 2 ⋅36863884301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20686772737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20686772137) 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, 1659123 + ... + 1671544.

It is an arithmetic number, because the mean of its divisors is an integer number (5172527404).

Almost surely, 2^20686772737 is an apocalyptic number.

It is an amenable number.

20686772737 is a deficient number, since it is larger than the sum of its proper divisors (3336879).

20686772737 is an equidigital number, since it uses as much as digits as its factorization.

20686772737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3336878.

The product of its (nonzero) digits is 8297856, while the sum is 55.

The spelling of 20686772737 in words is "twenty billion, six hundred eighty-six million, seven hundred seventy-two thousand, seven hundred thirty-seven".