21996220 has 24 divisors (see below), whose sum is σ = 47268144. Its totient is φ = 8593536.

The previous prime is 21996217. The next prime is 21996223. The reversal of 21996220 is 2269912.

It is an interprime number because it is at equal distance from previous prime (21996217) and next prime (21996223).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21996223) 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, 11929 + ... + 13648.

It is an arithmetic number, because the mean of its divisors is an integer number (1969506).

Almost surely, 2^21996220 is an apocalyptic number.

21996220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21996220 is an abundant number, since it is smaller than the sum of its proper divisors (25271924).

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

21996220 is a wasteful number, since it uses less digits than its factorization.

21996220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25629 (or 25627 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21996220 is about 4690.0127931595. The cubic root of 21996220 is about 280.1878841029.

The spelling of 21996220 in words is "twenty-one million, nine hundred ninety-six thousand, two hundred twenty".