640056451 has 4 divisors (see below), whose sum is σ = 657355312. Its totient is φ = 622757592.

The previous prime is 640056413. The next prime is 640056457. The reversal of 640056451 is 154650046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 154650046 = 2 ⋅77325023.

It is a cyclic number.

It is not a de Polignac number, because 640056451 - 2⁷ = 640056323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640056457) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8649375 + ... + 8649448.

It is an arithmetic number, because the mean of its divisors is an integer number (164338828).

Almost surely, 2^640056451 is an apocalyptic number.

640056451 is a deficient number, since it is larger than the sum of its proper divisors (17298861).

640056451 is a wasteful number, since it uses less digits than its factorization.

640056451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17298860.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 640056451 is about 25299.3369675966. The cubic root of 640056451 is about 861.7992127663.

The spelling of 640056451 in words is "six hundred forty million, fifty-six thousand, four hundred fifty-one".