640252426451261 has 32 divisors (see below), whose sum is σ = 701205416110080. Its totient is φ = 581063986368000.

The previous prime is 640252426451233. The next prime is 640252426451279. The reversal of 640252426451261 is 162154624252046.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640252426451261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640252426651261) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140452106 + ... + 144938948.

It is an arithmetic number, because the mean of its divisors is an integer number (21912669253440).

Almost surely, 2^{640252426451261} is an apocalyptic number.

It is an amenable number.

640252426451261 is a deficient number, since it is larger than the sum of its proper divisors (60952989658819).

640252426451261 is a wasteful number, since it uses less digits than its factorization.

640252426451261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4487717.

The product of its (nonzero) digits is 5529600, while the sum is 50.

The spelling of 640252426451261 in words is "six hundred forty trillion, two hundred fifty-two billion, four hundred twenty-six million, four hundred fifty-one thousand, two hundred sixty-one".