21998725 has 12 divisors (see below), whose sum is σ = 31175584. Its totient is φ = 15084720.

The previous prime is 21998723. The next prime is 21998749. The reversal of 21998725 is 52789912.

It is not a de Polignac number, because 21998725 - 2¹ = 21998723 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21998723) 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 11 ways as a sum of consecutive naturals, for example, 62679 + ... + 63028.

Almost surely, 2^21998725 is an apocalyptic number.

21998725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21998725 is a deficient number, since it is larger than the sum of its proper divisors (9176859).

21998725 is a wasteful number, since it uses less digits than its factorization.

21998725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125724 (or 125719 counting only the distinct ones).

The product of its digits is 90720, while the sum is 43.

The square root of 21998725 is about 4690.2798423975. The cubic root of 21998725 is about 280.1985199304.

The spelling of 21998725 in words is "twenty-one million, nine hundred ninety-eight thousand, seven hundred twenty-five".