645273974 has 4 divisors (see below), whose sum is σ = 967910964. Its totient is φ = 322636986.

The previous prime is 645273971. The next prime is 645273989. The reversal of 645273974 is 479372546.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645273971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161318492 + ... + 161318495.

It is an arithmetic number, because the mean of its divisors is an integer number (241977741).

Almost surely, 2^645273974 is an apocalyptic number.

645273974 is a deficient number, since it is larger than the sum of its proper divisors (322636990).

645273974 is a wasteful number, since it uses less digits than its factorization.

645273974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322636989.

The product of its digits is 1270080, while the sum is 47.

The square root of 645273974 is about 25402.2434835981. The cubic root of 645273974 is about 864.1345767667.

The spelling of 645273974 in words is "six hundred forty-five million, two hundred seventy-three thousand, nine hundred seventy-four".