25317509 has 16 divisors (see below), whose sum is σ = 29913600. Its totient is φ = 20974464.

The previous prime is 25317469. The next prime is 25317521. The reversal of 25317509 is 90571352.

25317509 = 15² + 16² + ... + 423².

It is not a de Polignac number, because 25317509 - 2¹⁶ = 25251973 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 (25317529) 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, 61697 + ... + 62105.

It is an arithmetic number, because the mean of its divisors is an integer number (1869600).

Almost surely, 2^25317509 is an apocalyptic number.

It is an amenable number.

25317509 is a deficient number, since it is larger than the sum of its proper divisors (4596091).

25317509 is a wasteful number, since it uses less digits than its factorization.

25317509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 25317509 is about 5031.6507231723. The cubic root of 25317509 is about 293.6344392888.

The spelling of 25317509 in words is "twenty-five million, three hundred seventeen thousand, five hundred nine".