21217914 has 48 divisors (see below), whose sum is σ = 48926592. Its totient is φ = 6630624.

The previous prime is 21217907. The next prime is 21217943. The reversal of 21217914 is 41971212.

It is a super-2 number, since 2×21217914² = 900399749022792, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21459 + ... + 22425.

It is an arithmetic number, because the mean of its divisors is an integer number (1019304).

Almost surely, 2^21217914 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21217914, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24463296).

21217914 is an abundant number, since it is smaller than the sum of its proper divisors (27708678).

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

21217914 is a wasteful number, since it uses less digits than its factorization.

21217914 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051 (or 1048 counting only the distinct ones).

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

The square root of 21217914 is about 4606.2906985990. The cubic root of 21217914 is about 276.8434343977.

The spelling of 21217914 in words is "twenty-one million, two hundred seventeen thousand, nine hundred fourteen".