21712977 has 24 divisors (see below), whose sum is σ = 36848448. Its totient is φ = 12146400.

The previous prime is 21712973. The next prime is 21712981. The reversal of 21712977 is 77921712.

It is an interprime number because it is at equal distance from previous prime (21712973) and next prime (21712981).

It is not a de Polignac number, because 21712977 - 2² = 21712973 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21712973) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7149 + ... + 9722.

It is an arithmetic number, because the mean of its divisors is an integer number (1535352).

Almost surely, 2^21712977 is an apocalyptic number.

It is an amenable number.

21712977 is a deficient number, since it is larger than the sum of its proper divisors (15135471).

21712977 is a wasteful number, since it uses less digits than its factorization.

21712977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16901 (or 16898 counting only the distinct ones).

The product of its digits is 12348, while the sum is 36.

The square root of 21712977 is about 4659.7185537326. The cubic root of 21712977 is about 278.9800347990.

The spelling of 21712977 in words is "twenty-one million, seven hundred twelve thousand, nine hundred seventy-seven".