20639398755 has 32 divisors (see below), whose sum is σ = 34775216640. Its totient is φ = 10424090880.

The previous prime is 20639398727. The next prime is 20639398757. The reversal of 20639398755 is 55789393602.

It is a happy number.

It is not a de Polignac number, because 20639398755 - 2⁸ = 20639398499 is a prime.

It is a super-3 number, since 3×20639398755³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a junction number, because it is equal to n+sod(n) for n = 20639398695 and 20639398704.

It is not an unprimeable number, because it can be changed into a prime (20639398757) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 759279 + ... + 785991.

It is an arithmetic number, because the mean of its divisors is an integer number (1086725520).

Almost surely, 2^20639398755 is an apocalyptic number.

20639398755 is a deficient number, since it is larger than the sum of its proper divisors (14135817885).

20639398755 is a wasteful number, since it uses less digits than its factorization.

20639398755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29451.

The product of its (nonzero) digits is 12247200, while the sum is 57.

The spelling of 20639398755 in words is "twenty billion, six hundred thirty-nine million, three hundred ninety-eight thousand, seven hundred fifty-five".