20813810 has 32 divisors (see below), whose sum is σ = 38502000. Its totient is φ = 8098560.

The previous prime is 20813791. The next prime is 20813813. The reversal of 20813810 is 1831802.

It can be written as a sum of positive squares in 8 ways, for example, as 4012009 + 16801801 = 2003^2 + 4099^2 .

It is a super-2 number, since 2×20813810² = 866429373432200, which contains 22 as substring.

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 in 15 ways as a sum of consecutive naturals, for example, 90776 + ... + 91004.

Almost surely, 2^20813810 is an apocalyptic number.

20813810 is a deficient number, since it is larger than the sum of its proper divisors (17688190).

20813810 is a wasteful number, since it uses less digits than its factorization.

20813810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 20813810 is about 4562.2154705801. The cubic root of 20813810 is about 275.0746243761.

The spelling of 20813810 in words is "twenty million, eight hundred thirteen thousand, eight hundred ten".