20731393 has 4 divisors (see below), whose sum is σ = 20964420. Its totient is φ = 20498368.

The previous prime is 20731391. The next prime is 20731397. The reversal of 20731393 is 39313702.

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 4787344 + 15944049 = 2188^2 + 3993^2 .

It is a cyclic number.

It is not a de Polignac number, because 20731393 - 2¹ = 20731391 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20731391) 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, 116380 + ... + 116557.

It is an arithmetic number, because the mean of its divisors is an integer number (5241105).

Almost surely, 2^20731393 is an apocalyptic number.

It is an amenable number.

20731393 is a deficient number, since it is larger than the sum of its proper divisors (233027).

20731393 is an equidigital number, since it uses as much as digits as its factorization.

20731393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233026.

The product of its (nonzero) digits is 3402, while the sum is 28.

The square root of 20731393 is about 4553.1739479181. The cubic root of 20731393 is about 274.7110706467.

The spelling of 20731393 in words is "twenty million, seven hundred thirty-one thousand, three hundred ninety-three".