21690960 has 40 divisors (see below), whose sum is σ = 67242720. Its totient is φ = 5784192.

The previous prime is 21690959. The next prime is 21690961. The reversal of 21690960 is 6909612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21690959) and next prime (21690961).

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690961) 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, 44950 + ... + 45429.

It is an arithmetic number, because the mean of its divisors is an integer number (1681068).

Almost surely, 2^21690960 is an apocalyptic number.

21690960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21690960 is an abundant number, since it is smaller than the sum of its proper divisors (45551760).

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

21690960 is a wasteful number, since it uses less digits than its factorization.

21690960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90395 (or 90389 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 21690960 is about 4657.3554727978. The cubic root of 21690960 is about 278.8857074804.

The spelling of 21690960 in words is "twenty-one million, six hundred ninety thousand, nine hundred sixty".