21679650 has 120 divisors (see below), whose sum is σ = 61981524. Its totient is φ = 5616000.

The previous prime is 21679631. The next prime is 21679661. The reversal of 21679650 is 5697612.

It can be written as a sum of positive squares in 6 ways, for example, as 16329681 + 5349969 = 4041^2 + 2313^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 214600 + ... + 214700.

Almost surely, 2^21679650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21679650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30990762).

21679650 is an abundant number, since it is smaller than the sum of its proper divisors (40301874).

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

21679650 is a wasteful number, since it uses less digits than its factorization.

21679650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 21679650 is about 4656.1411061092. The cubic root of 21679650 is about 278.8372272883.

The spelling of 21679650 in words is "twenty-one million, six hundred seventy-nine thousand, six hundred fifty".