20949813 has 8 divisors (see below), whose sum is σ = 31036800. Its totient is φ = 13966524.

The previous prime is 20949809. The next prime is 20949823. The reversal of 20949813 is 31894902.

It is not a de Polignac number, because 20949813 - 2² = 20949809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20949823) 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, 387933 + ... + 387986.

It is an arithmetic number, because the mean of its divisors is an integer number (3879600).

Almost surely, 2^20949813 is an apocalyptic number.

It is an amenable number.

20949813 is a deficient number, since it is larger than the sum of its proper divisors (10086987).

20949813 is an equidigital number, since it uses as much as digits as its factorization.

20949813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775928 (or 775922 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 20949813 is about 4577.0965687868. The cubic root of 20949813 is about 275.6724611684.

The spelling of 20949813 in words is "twenty million, nine hundred forty-nine thousand, eight hundred thirteen".