21977774 has 36 divisors (see below), whose sum is σ = 41557104. Its totient is φ = 8687952.

The previous prime is 21977771. The next prime is 21977777. The reversal of 21977774 is 47777912.

It is an interprime number because it is at equal distance from previous prime (21977771) and next prime (21977777).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977771) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 15899 + ... + 17225.

It is an arithmetic number, because the mean of its divisors is an integer number (1154364).

Almost surely, 2^21977774 is an apocalyptic number.

21977774 is a deficient number, since it is larger than the sum of its proper divisors (19579330).

21977774 is a wasteful number, since it uses less digits than its factorization.

21977774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1369 (or 1349 counting only the distinct ones).

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

The square root of 21977774 is about 4688.0458615504. The cubic root of 21977774 is about 280.1095404738.

The spelling of 21977774 in words is "twenty-one million, nine hundred seventy-seven thousand, seven hundred seventy-four".