20722637 has 4 divisors (see below), whose sum is σ = 22316700. Its totient is φ = 19128576.

The previous prime is 20722621. The next prime is 20722649. The reversal of 20722637 is 73622702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5621641 + 15100996 = 2371^2 + 3886^2 .

It is a cyclic number.

It is not a de Polignac number, because 20722637 - 2⁴ = 20722621 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 (20722687) 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, 797012 + ... + 797037.

It is an arithmetic number, because the mean of its divisors is an integer number (5579175).

Almost surely, 2^20722637 is an apocalyptic number.

It is an amenable number.

20722637 is a deficient number, since it is larger than the sum of its proper divisors (1594063).

20722637 is a wasteful number, since it uses less digits than its factorization.

20722637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1594062.

The product of its (nonzero) digits is 7056, while the sum is 29.

The square root of 20722637 is about 4552.2123193015. The cubic root of 20722637 is about 274.6723900356.

The spelling of 20722637 in words is "twenty million, seven hundred twenty-two thousand, six hundred thirty-seven".