21977477 has 8 divisors (see below), whose sum is σ = 22336512. Its totient is φ = 21621600.

The previous prime is 21977399. The next prime is 21977491. The reversal of 21977477 is 77477912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21977477 - 2¹⁸ = 21715333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15977 + ... + 17297.

It is an arithmetic number, because the mean of its divisors is an integer number (2792064).

Almost surely, 2^21977477 is an apocalyptic number.

It is an amenable number.

21977477 is a deficient number, since it is larger than the sum of its proper divisors (359035).

21977477 is a wasteful number, since it uses less digits than its factorization.

21977477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579.

The product of its digits is 172872, while the sum is 44.

The square root of 21977477 is about 4688.0141851321. The cubic root of 21977477 is about 280.1082787004.

The spelling of 21977477 in words is "twenty-one million, nine hundred seventy-seven thousand, four hundred seventy-seven".