20631309 has 8 divisors (see below), whose sum is σ = 27540480. Its totient is φ = 13738176.

The previous prime is 20631293. The next prime is 20631343. The reversal of 20631309 is 90313602.

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

It is not a de Polignac number, because 20631309 - 2⁴ = 20631293 is a prime.

It is a super-2 number, since 2×20631309² = 851301822106962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20631389) 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, 589 + ... + 6450.

It is an arithmetic number, because the mean of its divisors is an integer number (3442560).

Almost surely, 2^20631309 is an apocalyptic number.

It is an amenable number.

20631309 is a deficient number, since it is larger than the sum of its proper divisors (6909171).

20631309 is an equidigital number, since it uses as much as digits as its factorization.

20631309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8019.

The product of its (nonzero) digits is 972, while the sum is 24.

The square root of 20631309 is about 4542.1700760760. The cubic root of 20631309 is about 274.2682873120.

The spelling of 20631309 in words is "twenty million, six hundred thirty-one thousand, three hundred nine".