20813812 has 6 divisors (see below), whose sum is σ = 36424178. Its totient is φ = 10406904.

The previous prime is 20813791. The next prime is 20813813. The reversal of 20813812 is 21831802.

It can be written as a sum of positive squares in only one way, i.e., 18011536 + 2802276 = 4244^2 + 1674^2 .

It is a super-3 number, since 3×20813812³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20813813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2601723 + ... + 2601730.

Almost surely, 2^20813812 is an apocalyptic number.

It is an amenable number.

20813812 is a deficient number, since it is larger than the sum of its proper divisors (15610366).

20813812 is a wasteful number, since it uses less digits than its factorization.

20813812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5203457 (or 5203455 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 20813812 is about 4562.2156897718. The cubic root of 20813812 is about 275.0746331867.

The spelling of 20813812 in words is "twenty million, eight hundred thirteen thousand, eight hundred twelve".