21199625 has 16 divisors (see below), whose sum is σ = 26631696. Its totient is φ = 16848000.

The previous prime is 21199613. The next prime is 21199627. The reversal of 21199625 is 52699112.

It can be written as a sum of positive squares in 8 ways, for example, as 18731584 + 2468041 = 4328^2 + 1571^2 .

It is not a de Polignac number, because 21199625 - 2⁸ = 21199369 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21199627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22157 + ... + 23093.

It is an arithmetic number, because the mean of its divisors is an integer number (1664481).

Almost surely, 2^21199625 is an apocalyptic number.

21199625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21199625 is a deficient number, since it is larger than the sum of its proper divisors (5432071).

21199625 is an equidigital number, since it uses as much as digits as its factorization.

21199625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1133 (or 1123 counting only the distinct ones).

The product of its digits is 9720, while the sum is 35.

The square root of 21199625 is about 4604.3050507107. The cubic root of 21199625 is about 276.7638688472.

The spelling of 21199625 in words is "twenty-one million, one hundred ninety-nine thousand, six hundred twenty-five".