21277716440 has 32 divisors (see below), whose sum is σ = 49525722000. Its totient is φ = 8217600384.

The previous prime is 21277716431. The next prime is 21277716479. The reversal of 21277716440 is 4461777212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9170270 + ... + 9172589.

Almost surely, 2^21277716440 is an apocalyptic number.

21277716440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21277716440 is an abundant number, since it is smaller than the sum of its proper divisors (28248005560).

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

21277716440 is a wasteful number, since it uses less digits than its factorization.

21277716440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18342899 (or 18342895 counting only the distinct ones).

The product of its (nonzero) digits is 131712, while the sum is 41.

The spelling of 21277716440 in words is "twenty-one billion, two hundred seventy-seven million, seven hundred sixteen thousand, four hundred forty".