645257426 has 24 divisors (see below), whose sum is σ = 1089839772. Its totient is φ = 286140800.

The previous prime is 645257411. The next prime is 645257429. The reversal of 645257426 is 624752546.

It can be written as a sum of positive squares in 2 ways, for example, as 645109201 + 148225 = 25399^2 + 385^2 .

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645257429) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22595 + ... + 42438.

Almost surely, 2^645257426 is an apocalyptic number.

645257426 is a deficient number, since it is larger than the sum of its proper divisors (444582346).

645257426 is a wasteful number, since it uses less digits than its factorization.

645257426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65098 (or 65087 counting only the distinct ones).

The product of its digits is 403200, while the sum is 41.

The square root of 645257426 is about 25401.9177622478. The cubic root of 645257426 is about 864.1271898159.

The spelling of 645257426 in words is "six hundred forty-five million, two hundred fifty-seven thousand, four hundred twenty-six".