21717400 has 24 divisors (see below), whose sum is σ = 50493420. Its totient is φ = 8686880.

The previous prime is 21717383. The next prime is 21717407. The reversal of 21717400 is 471712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21717407) 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, 54094 + ... + 54493.

Almost surely, 2^21717400 is an apocalyptic number.

21717400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21717400 is an abundant number, since it is smaller than the sum of its proper divisors (28776020).

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

21717400 is a wasteful number, since it uses less digits than its factorization.

21717400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108603 (or 108594 counting only the distinct ones).

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 21717400 is about 4660.1931290452. The cubic root of 21717400 is about 278.9989765425.

The spelling of 21717400 in words is "twenty-one million, seven hundred seventeen thousand, four hundred".