20815944867 has 16 divisors (see below), whose sum is σ = 31228800000. Its totient is φ = 13701633192.

The previous prime is 20815944859. The next prime is 20815944901. The reversal of 20815944867 is 76844951802.

It is a happy number.

20815944867 is a `hidden beast` number, since 2 + 0 + 8 + 1 + 594 + 48 + 6 + 7 = 666.

It is not a de Polignac number, because 20815944867 - 2³ = 20815944859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20815944857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4877367 + ... + 4881632.

It is an arithmetic number, because the mean of its divisors is an integer number (1951800000).

Almost surely, 2^20815944867 is an apocalyptic number.

20815944867 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

20815944867 is a deficient number, since it is larger than the sum of its proper divisors (10412855133).

20815944867 is an equidigital number, since it uses as much as digits as its factorization.

20815944867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9759087 (or 9759081 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 20815944867 in words is "twenty billion, eight hundred fifteen million, nine hundred forty-four thousand, eight hundred sixty-seven".