21977154 has 12 divisors (see below), whose sum is σ = 47617206. Its totient is φ = 7325712.

The previous prime is 21977147. The next prime is 21977159. The reversal of 21977154 is 45177912.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20930625 + 1046529 = 4575^2 + 1023^2 .

It is not an unprimeable number, because it can be changed into a prime (21977159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 610459 + ... + 610494.

Almost surely, 2^21977154 is an apocalyptic number.

21977154 is an abundant number, since it is smaller than the sum of its proper divisors (25640052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21977154 is a wasteful number, since it uses less digits than its factorization.

21977154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1220961 (or 1220958 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 21977154 is about 4687.9797354511. The cubic root of 21977154 is about 280.1069064559.

The spelling of 21977154 in words is "twenty-one million, nine hundred seventy-seven thousand, one hundred fifty-four".