20631513 has 8 divisors (see below), whose sum is σ = 31438528. Its totient is φ = 11789424.

The previous prime is 20631509. The next prime is 20631547. The reversal of 20631513 is 31513602.

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

It is not a de Polignac number, because 20631513 - 2² = 20631509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 982453 = 20631513 / (2 + 0 + 6 + 3 + 1 + 5 + 1 + 3).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20631513.

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 7 ways as a sum of consecutive naturals, for example, 491206 + ... + 491247.

It is an arithmetic number, because the mean of its divisors is an integer number (3929816).

Almost surely, 2^20631513 is an apocalyptic number.

It is an amenable number.

20631513 is a deficient number, since it is larger than the sum of its proper divisors (10807015).

20631513 is an equidigital number, since it uses as much as digits as its factorization.

20631513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982463.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 20631513 is about 4542.1925322470. The cubic root of 20631513 is about 274.2691912867.

The spelling of 20631513 in words is "twenty million, six hundred thirty-one thousand, five hundred thirteen".