21499968 has 112 divisors (see below), whose sum is σ = 68909184. Its totient is φ = 5775360.

The previous prime is 21499967. The next prime is 21499969. The reversal of 21499968 is 86999412.

It is an interprime number because it is at equal distance from previous prime (21499967) and next prime (21499969).

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21499967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22378 + ... + 23318.

Almost surely, 2^21499968 is an apocalyptic number.

21499968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21499968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34454592).

21499968 is an abundant number, since it is smaller than the sum of its proper divisors (47409216).

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

21499968 is a wasteful number, since it uses less digits than its factorization.

21499968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 980 (or 970 counting only the distinct ones).

The product of its digits is 279936, while the sum is 48.

The square root of 21499968 is about 4636.8057970978. The cubic root of 21499968 is about 278.0647503713.

The spelling of 21499968 in words is "twenty-one million, four hundred ninety-nine thousand, nine hundred sixty-eight".