21981046977 has 48 divisors (see below), whose sum is σ = 34155777600. Its totient is φ = 13962836160.

The previous prime is 21981046963. The next prime is 21981046991. The reversal of 21981046977 is 77964018912.

21981046977 is a `hidden beast` number, since 21 + 98 + 1 + 0 + 469 + 77 = 666.

It is an interprime number because it is at equal distance from previous prime (21981046963) and next prime (21981046991).

It is not a de Polignac number, because 21981046977 - 2¹⁰ = 21981045953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21981146977) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2041474 + ... + 2052212.

It is an arithmetic number, because the mean of its divisors is an integer number (711578700).

Almost surely, 2^21981046977 is an apocalyptic number.

21981046977 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21981046977 is a deficient number, since it is larger than the sum of its proper divisors (12174730623).

21981046977 is a wasteful number, since it uses less digits than its factorization.

21981046977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10875 (or 10826 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 54.

The spelling of 21981046977 in words is "twenty-one billion, nine hundred eighty-one million, forty-six thousand, nine hundred seventy-seven".