640297427 has 8 divisors (see below), whose sum is σ = 798292992. Its totient is φ = 498933000.

The previous prime is 640297363. The next prime is 640297429. The reversal of 640297427 is 724792046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640297427 - 2⁶ = 640297363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640297429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4157699 + ... + 4157852.

It is an arithmetic number, because the mean of its divisors is an integer number (99786624).

Almost surely, 2^640297427 is an apocalyptic number.

640297427 is a deficient number, since it is larger than the sum of its proper divisors (157995565).

640297427 is a wasteful number, since it uses less digits than its factorization.

640297427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8315569.

The product of its (nonzero) digits is 169344, while the sum is 41.

The square root of 640297427 is about 25304.0990157721. The cubic root of 640297427 is about 861.9073526394.

The spelling of 640297427 in words is "six hundred forty million, two hundred ninety-seven thousand, four hundred twenty-seven".