21325739 has 2 divisors, whose sum is σ = 21325740. Its totient is φ = 21325738.

The previous prime is 21325693. The next prime is 21325757. The reversal of 21325739 is 93752312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21325739 is a prime.

It is a super-2 number, since 2×21325739² = 909574287792242, which contains 22 as substring.

It is a plaindrome in base 16.

It is not a weakly prime, because it can be changed into another prime (21324739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662869 + 10662870.

It is an arithmetic number, because the mean of its divisors is an integer number (10662870).

Almost surely, 2^21325739 is an apocalyptic number.

21325739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21325739 is an equidigital number, since it uses as much as digits as its factorization.

21325739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 32.

The square root of 21325739 is about 4617.9799696404. The cubic root of 21325739 is about 277.3115957303.

It can be divided in two parts, 213 and 25739, that added together give a palindrome (25952).

The spelling of 21325739 in words is "twenty-one million, three hundred twenty-five thousand, seven hundred thirty-nine".