20638310957 has 4 divisors (see below), whose sum is σ = 22514521056. Its totient is φ = 18762100860.

The previous prime is 20638310939. The next prime is 20638310963. The reversal of 20638310957 is 75901383602.

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.

It is a cyclic number.

It is not a de Polignac number, because 20638310957 - 2⁶ = 20638310893 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 (20638316957) 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, 938105033 + ... + 938105054.

It is an arithmetic number, because the mean of its divisors is an integer number (5628630264).

Almost surely, 2^20638310957 is an apocalyptic number.

It is an amenable number.

20638310957 is a deficient number, since it is larger than the sum of its proper divisors (1876210099).

20638310957 is a wasteful number, since it uses less digits than its factorization.

20638310957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876210098.

The product of its (nonzero) digits is 272160, while the sum is 44.

The spelling of 20638310957 in words is "twenty billion, six hundred thirty-eight million, three hundred ten thousand, nine hundred fifty-seven".