21995830 has 16 divisors (see below), whose sum is σ = 40071024. Its totient is φ = 8692000.

The previous prime is 21995801. The next prime is 21995839. The reversal of 21995830 is 3859912.

It is a self number, because there is not a number n which added to its sum of digits gives 21995830.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21995839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12421 + ... + 14080.

It is an arithmetic number, because the mean of its divisors is an integer number (2504439).

Almost surely, 2^21995830 is an apocalyptic number.

21995830 is a deficient number, since it is larger than the sum of its proper divisors (18075194).

21995830 is a wasteful number, since it uses less digits than its factorization.

21995830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26591.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 21995830 is about 4689.9712152635. The cubic root of 21995830 is about 280.1862281529.

The spelling of 21995830 in words is "twenty-one million, nine hundred ninety-five thousand, eight hundred thirty".