20827881 has 8 divisors (see below), whose sum is σ = 30856160. Its totient is φ = 13885236.

The previous prime is 20827861. The next prime is 20827897. The reversal of 20827881 is 18872802.

20827881 = 275² + 276² + ... + 436².

It is not a de Polignac number, because 20827881 - 2¹⁵ = 20795113 is a prime.

It is a super-2 number, since 2×20827881² = 867601253900322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20827831) 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, 385675 + ... + 385728.

It is an arithmetic number, because the mean of its divisors is an integer number (3857020).

Almost surely, 2^20827881 is an apocalyptic number.

It is an amenable number.

20827881 is a deficient number, since it is larger than the sum of its proper divisors (10028279).

20827881 is an equidigital number, since it uses as much as digits as its factorization.

20827881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771412 (or 771406 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 20827881 is about 4563.7573336013. The cubic root of 20827881 is about 275.1365977028.

The spelling of 20827881 in words is "twenty million, eight hundred twenty-seven thousand, eight hundred eighty-one".