21917412 has 96 divisors (see below), whose sum is σ = 65318400. Its totient is φ = 6285600.

The previous prime is 21917351. The next prime is 21917419. The reversal of 21917412 is 21471912.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21917419) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22087 + ... + 23057.

It is an arithmetic number, because the mean of its divisors is an integer number (680400).

Almost surely, 2^21917412 is an apocalyptic number.

21917412 is a gapful number since it is divisible by the number (22) 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 21917412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32659200).

21917412 is an abundant number, since it is smaller than the sum of its proper divisors (43400988).

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

21917412 is a wasteful number, since it uses less digits than its factorization.

21917412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014 (or 1006 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 21917412 is about 4681.6035714272. The cubic root of 21917412 is about 279.8528648735.

The spelling of 21917412 in words is "twenty-one million, nine hundred seventeen thousand, four hundred twelve".