27997821720 has 160 divisors (see below), whose sum is σ = 102658810320. Its totient is φ = 6787342080.

The previous prime is 27997821701. The next prime is 27997821727. The reversal of 27997821720 is 2712879972.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27997821727) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 357147 + ... + 428426.

Almost surely, 2^27997821720 is an apocalyptic number.

27997821720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

27997821720 is an abundant number, since it is smaller than the sum of its proper divisors (74660988600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

27997821720 is a wasteful number, since it uses less digits than its factorization.

27997821720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785607 (or 785594 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 54.

The spelling of 27997821720 in words is "twenty-seven billion, nine hundred ninety-seven million, eight hundred twenty-one thousand, seven hundred twenty".