645123025 has 6 divisors (see below), whose sum is σ = 799952582. Its totient is φ = 516098400.

The previous prime is 645122983. The next prime is 645123029. The reversal of 645123025 is 520321546.

It can be written as a sum of positive squares in 3 ways, for example, as 68690944 + 576432081 = 8288^2 + 24009^2 .

It is not a de Polignac number, because 645123025 - 2⁷ = 645122897 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645122984 and 645123002.

It is not an unprimeable number, because it can be changed into a prime (645123029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12902436 + ... + 12902485.

Almost surely, 2^645123025 is an apocalyptic number.

It is an amenable number.

645123025 is a deficient number, since it is larger than the sum of its proper divisors (154829557).

645123025 is a wasteful number, since it uses less digits than its factorization.

645123025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25804931 (or 25804926 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 645123025 is about 25399.2721352404. The cubic root of 645123025 is about 864.0671891515.

The spelling of 645123025 in words is "six hundred forty-five million, one hundred twenty-three thousand, twenty-five".