640254466 has 4 divisors (see below), whose sum is σ = 960381702. Its totient is φ = 320127232.

The previous prime is 640254463. The next prime is 640254487. The reversal of 640254466 is 664452046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 664452046 = 2 ⋅332226023.

It can be written as a sum of positive squares in only one way, i.e., 333829441 + 306425025 = 18271^2 + 17505^2 .

It is not an unprimeable number, because it can be changed into a prime (640254463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160063615 + ... + 160063618.

Almost surely, 2^640254466 is an apocalyptic number.

640254466 is a deficient number, since it is larger than the sum of its proper divisors (320127236).

640254466 is a wasteful number, since it uses less digits than its factorization.

640254466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320127235.

The product of its (nonzero) digits is 138240, while the sum is 37.

The square root of 640254466 is about 25303.2501074467. The cubic root of 640254466 is about 861.8880755408. Note that the first 3 decimals are identical.

The spelling of 640254466 in words is "six hundred forty million, two hundred fifty-four thousand, four hundred sixty-six".