640156273 has 2 divisors, whose sum is σ = 640156274. Its totient is φ = 640156272.

The previous prime is 640156243. The next prime is 640156289. The reversal of 640156273 is 372651046.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 413593569 + 226562704 = 20337^2 + 15052^2 .

It is a cyclic number.

It is not a de Polignac number, because 640156273 - 2⁵ = 640156241 is a prime.

It is a super-2 number, since 2×640156273² = 819600107722501058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (640156213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320078136 + 320078137.

It is an arithmetic number, because the mean of its divisors is an integer number (320078137).

Almost surely, 2^640156273 is an apocalyptic number.

It is an amenable number.

640156273 is a deficient number, since it is larger than the sum of its proper divisors (1).

640156273 is an equidigital number, since it uses as much as digits as its factorization.

640156273 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 640156273 is about 25301.3097091830. The cubic root of 640156273 is about 861.8440119654.

The spelling of 640156273 in words is "six hundred forty million, one hundred fifty-six thousand, two hundred seventy-three".