640818827 has 8 divisors (see below), whose sum is σ = 705609792. Its totient is φ = 577117000.

The previous prime is 640818823. The next prime is 640818839. The reversal of 640818827 is 728818046.

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 640818827 - 2² = 640818823 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640818823) 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, 271049 + ... + 273402.

It is an arithmetic number, because the mean of its divisors is an integer number (88201224).

Almost surely, 2^640818827 is an apocalyptic number.

640818827 is a deficient number, since it is larger than the sum of its proper divisors (64790965).

640818827 is a wasteful number, since it uses less digits than its factorization.

640818827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544569.

The product of its (nonzero) digits is 172032, while the sum is 44.

The square root of 640818827 is about 25314.3995978573. The cubic root of 640818827 is about 862.1412421553.

The spelling of 640818827 in words is "six hundred forty million, eight hundred eighteen thousand, eight hundred twenty-seven".