20815944808477 has 64 divisors (see below), whose sum is σ = 26245791936000. Its totient is φ = 16404766479360.

The previous prime is 20815944808427. The next prime is 20815944808489. The reversal of 20815944808477 is 77480844951802.

It is not a de Polignac number, because 20815944808477 - 2³¹ = 20813797324829 is a prime.

It is a super-2 number, since 2×20815944808477² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20815944808427) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1666469202 + ... + 1666481692.

It is an arithmetic number, because the mean of its divisors is an integer number (410090499000).

Almost surely, 2^{20815944808477} is an apocalyptic number.

It is an amenable number.

20815944808477 is a deficient number, since it is larger than the sum of its proper divisors (5429847127523).

20815944808477 is a wasteful number, since it uses less digits than its factorization.

20815944808477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13971 (or 13957 counting only the distinct ones).

The product of its (nonzero) digits is 144506880, while the sum is 67.

The spelling of 20815944808477 in words is "twenty trillion, eight hundred fifteen billion, nine hundred forty-four million, eight hundred eight thousand, four hundred seventy-seven".