25191989 has 2 divisors, whose sum is σ = 25191990. Its totient is φ = 25191988.

The previous prime is 25191979. The next prime is 25192001. The reversal of 25191989 is 98919152.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21022225 + 4169764 = 4585^2 + 2042^2 .

It is a cyclic number.

It is not a de Polignac number, because 25191989 - 2²⁴ = 8414773 is a prime.

It is a super-2 number, since 2×25191989² = 1269272619552242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25191919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12595994 + 12595995.

It is an arithmetic number, because the mean of its divisors is an integer number (12595995).

Almost surely, 2^25191989 is an apocalyptic number.

It is an amenable number.

25191989 is a deficient number, since it is larger than the sum of its proper divisors (1).

25191989 is an equidigital number, since it uses as much as digits as its factorization.

25191989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 44.

The square root of 25191989 is about 5019.1621810816. The cubic root of 25191989 is about 293.1483715451.

The spelling of 25191989 in words is "twenty-five million, one hundred ninety-one thousand, nine hundred eighty-nine".