21430988 has 12 divisors (see below), whose sum is σ = 37876272. Its totient is φ = 10609200.

The previous prime is 21430979. The next prime is 21430991. The reversal of 21430988 is 88903412.

It is a happy number.

It is a super-2 number, since 2×21430988² = 918574493312288, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26120 + ... + 26927.

It is an arithmetic number, because the mean of its divisors is an integer number (3156356).

Almost surely, 2^21430988 is an apocalyptic number.

It is an amenable number.

21430988 is a deficient number, since it is larger than the sum of its proper divisors (16445284).

21430988 is a wasteful number, since it uses less digits than its factorization.

21430988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53152 (or 53150 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 21430988 is about 4629.3615110510. The cubic root of 21430988 is about 277.7670529311.

The spelling of 21430988 in words is "twenty-one million, four hundred thirty thousand, nine hundred eighty-eight".