20720631 has 8 divisors (see below), whose sum is σ = 28828800. Its totient is φ = 13213112.

The previous prime is 20720611. The next prime is 20720633. The reversal of 20720631 is 13602702.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20720631 - 2⁵ = 20720599 is a prime.

It is a super-2 number, since 2×20720631² = 858689098076322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20720598 and 20720607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150081 + ... + 150218.

It is an arithmetic number, because the mean of its divisors is an integer number (3603600).

Almost surely, 2^20720631 is an apocalyptic number.

20720631 is a deficient number, since it is larger than the sum of its proper divisors (8108169).

20720631 is a wasteful number, since it uses less digits than its factorization.

20720631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300325.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 20720631 is about 4551.9919815395. The cubic root of 20720631 is about 274.6635267718.

The spelling of 20720631 in words is "twenty million, seven hundred twenty thousand, six hundred thirty-one".