21789930 has 16 divisors (see below), whose sum is σ = 52295904. Its totient is φ = 5810640.

The previous prime is 21789919. The next prime is 21789967. The reversal of 21789930 is 3998712.

21789930 = T₂₁₉₆ + T₂₁₉₇ + ... + T₂₂₀₄.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 363136 + ... + 363195.

It is an arithmetic number, because the mean of its divisors is an integer number (3268494).

Almost surely, 2^21789930 is an apocalyptic number.

21789930 is an abundant number, since it is smaller than the sum of its proper divisors (30505974).

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

21789930 is a wasteful number, since it uses less digits than its factorization.

21789930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726341.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 21789930 is about 4667.9685088912. The cubic root of 21789930 is about 279.3092240888.

The spelling of 21789930 in words is "twenty-one million, seven hundred eighty-nine thousand, nine hundred thirty".