20701957 has 4 divisors (see below), whose sum is σ = 20711916. Its totient is φ = 20692000.

The previous prime is 20701951. The next prime is 20701973. The reversal of 20701957 is 75910702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 6155361 + 14546596 = 2481^2 + 3814^2 .

It is a cyclic number.

It is not a de Polignac number, because 20701957 - 2¹⁵ = 20669189 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20701951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 544 + ... + 6457.

It is an arithmetic number, because the mean of its divisors is an integer number (5177979).

It is a vampire number, since it can be written as 2957 ⋅ 7001 (with its own digits).

Almost surely, 2^20701957 is an apocalyptic number.

It is an amenable number.

20701957 is a deficient number, since it is larger than the sum of its proper divisors (9959).

20701957 is an equidigital number, since it uses as much as digits as its factorization.

20701957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9958.

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 20701957 is about 4549.9403292791. The cubic root of 20701957 is about 274.5809905419.

The spelling of 20701957 in words is "twenty million, seven hundred one thousand, nine hundred fifty-seven".