21954280 has 32 divisors (see below), whose sum is σ = 49546440. Its totient is φ = 8755200.

The previous prime is 21954263. The next prime is 21954281. The reversal of 21954280 is 8245912.

It can be written as a sum of positive squares in 4 ways, for example, as 14303524 + 7650756 = 3782^2 + 2766^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21954281) 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, 17680 + ... + 18880.

Almost surely, 2^21954280 is an apocalyptic number.

21954280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21954280 is an abundant number, since it is smaller than the sum of its proper divisors (27592160).

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

21954280 is a wasteful number, since it uses less digits than its factorization.

21954280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1669 (or 1665 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 21954280 is about 4685.5394566688. The cubic root of 21954280 is about 280.0096935420.

The spelling of 21954280 in words is "twenty-one million, nine hundred fifty-four thousand, two hundred eighty".