21180294477 has 20 divisors (see below), whose sum is σ = 31781608320. Its totient is φ = 14056865064.

The previous prime is 21180294469. The next prime is 21180294589. The reversal of 21180294477 is 77449208112.

21180294477 is a `hidden beast` number, since 2 + 1 + 180 + 29 + 447 + 7 = 666.

It is not a de Polignac number, because 21180294477 - 2³ = 21180294469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180294077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 568227 + ... + 604352.

It is an arithmetic number, because the mean of its divisors is an integer number (1589080416).

Almost surely, 2^21180294477 is an apocalyptic number.

21180294477 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21180294477 is a deficient number, since it is larger than the sum of its proper divisors (10601313843).

21180294477 is a wasteful number, since it uses less digits than its factorization.

21180294477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172814 (or 1172805 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The spelling of 21180294477 in words is "twenty-one billion, one hundred eighty million, two hundred ninety-four thousand, four hundred seventy-seven".