20631553 has 4 divisors (see below), whose sum is σ = 20644308. Its totient is φ = 20618800.

The previous prime is 20631547. The next prime is 20631563. The reversal of 20631553 is 35513602.

It is a happy number.

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 5793649 + 14837904 = 2407^2 + 3852^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20631553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20631503) 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, 3526 + ... + 7327.

It is an arithmetic number, because the mean of its divisors is an integer number (5161077).

Almost surely, 2^20631553 is an apocalyptic number.

It is an amenable number.

20631553 is a deficient number, since it is larger than the sum of its proper divisors (12755).

20631553 is a wasteful number, since it uses less digits than its factorization.

20631553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12754.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 20631553 is about 4542.1969354047. The cubic root of 20631553 is about 274.2693685360.

The spelling of 20631553 in words is "twenty million, six hundred thirty-one thousand, five hundred fifty-three".