21325749 has 4 divisors (see below), whose sum is σ = 28434336. Its totient is φ = 14217164.

The previous prime is 21325739. The next prime is 21325757. The reversal of 21325749 is 94752312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21325749 - 2²¹ = 19228597 is a prime.

It is a super-2 number, since 2×21325749² = 909575140822002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21325739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3554289 + ... + 3554294.

It is an arithmetic number, because the mean of its divisors is an integer number (7108584).

Almost surely, 2^21325749 is an apocalyptic number.

It is an amenable number.

21325749 is a deficient number, since it is larger than the sum of its proper divisors (7108587).

21325749 is an equidigital number, since it uses as much as digits as its factorization.

21325749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7108586.

The product of its digits is 15120, while the sum is 33.

The square root of 21325749 is about 4617.9810523648. The cubic root of 21325749 is about 277.3116390757.

The spelling of 21325749 in words is "twenty-one million, three hundred twenty-five thousand, seven hundred forty-nine".