20772431 has 4 divisors (see below), whose sum is σ = 20781792. Its totient is φ = 20763072.

The previous prime is 20772403. The next prime is 20772443. The reversal of 20772431 is 13427702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 13427702 = 2 ⋅6713851.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20772431 is a prime.

It is a super-2 number, since 2×20772431² = 862987779299522, which contains 22 as substring.

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 20772431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20772481) 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, 746 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (5195448).

Almost surely, 2^20772431 is an apocalyptic number.

20772431 is a deficient number, since it is larger than the sum of its proper divisors (9361).

20772431 is an equidigital number, since it uses as much as digits as its factorization.

20772431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9360.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 20772431 is about 4557.6782466515. The cubic root of 20772431 is about 274.8922156114.

The spelling of 20772431 in words is "twenty million, seven hundred seventy-two thousand, four hundred thirty-one".