21974780 has 24 divisors (see below), whose sum is σ = 46252080. Its totient is φ = 8769920.

The previous prime is 21974767. The next prime is 21974789. The reversal of 21974780 is 8747912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10415 + ... + 12345.

It is an arithmetic number, because the mean of its divisors is an integer number (1927170).

Almost surely, 2^21974780 is an apocalyptic number.

21974780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21974780 is an abundant number, since it is smaller than the sum of its proper divisors (24277300).

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

21974780 is a wasteful number, since it uses less digits than its factorization.

21974780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2509 (or 2507 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 21974780 is about 4687.7265278597. The cubic root of 21974780 is about 280.0968202585.

The spelling of 21974780 in words is "twenty-one million, nine hundred seventy-four thousand, seven hundred eighty".