21461940 has 36 divisors (see below), whose sum is σ = 65101764. Its totient is φ = 5723136.

The previous prime is 21461917. The next prime is 21461941. The reversal of 21461940 is 4916412.

21461940 is a `hidden beast` number, since 2 + 1 + 4 + 619 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 5253264 + 16208676 = 2292^2 + 4026^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21461940² = 921229737127200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59437 + ... + 59796.

Almost surely, 2^21461940 is an apocalyptic number.

21461940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21461940 is an abundant number, since it is smaller than the sum of its proper divisors (43639824).

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

21461940 is a wasteful number, since it uses less digits than its factorization.

21461940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119248 (or 119243 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21461940 is about 4632.7033144806. The cubic root of 21461940 is about 277.9007115714.

The spelling of 21461940 in words is "twenty-one million, four hundred sixty-one thousand, nine hundred forty".