20747431 has 2 divisors, whose sum is σ = 20747432. Its totient is φ = 20747430.

The previous prime is 20747423. The next prime is 20747437. The reversal of 20747431 is 13474702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20747431 - 2³ = 20747423 is a prime.

It is a super-2 number, since 2×20747431² = 860911786199522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20747431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20747437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10373715 + 10373716.

It is an arithmetic number, because the mean of its divisors is an integer number (10373716).

Almost surely, 2^20747431 is an apocalyptic number.

20747431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20747431 is an equidigital number, since it uses as much as digits as its factorization.

20747431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4704, while the sum is 28.

The square root of 20747431 is about 4554.9347964598. The cubic root of 20747431 is about 274.7818920738.

The spelling of 20747431 in words is "twenty million, seven hundred forty-seven thousand, four hundred thirty-one".