646275261 has 4 divisors (see below), whose sum is σ = 861700352. Its totient is φ = 430850172.

The previous prime is 646275257. The next prime is 646275283. The reversal of 646275261 is 162572646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 646275261 - 2² = 646275257 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 (646275211) 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, 107712541 + ... + 107712546.

It is an arithmetic number, because the mean of its divisors is an integer number (215425088).

Almost surely, 2^646275261 is an apocalyptic number.

It is an amenable number.

646275261 is a deficient number, since it is larger than the sum of its proper divisors (215425091).

646275261 is a wasteful number, since it uses less digits than its factorization.

646275261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215425090.

The product of its digits is 120960, while the sum is 39.

The square root of 646275261 is about 25421.9444771638. The cubic root of 646275261 is about 864.5813118471.

The spelling of 646275261 in words is "six hundred forty-six million, two hundred seventy-five thousand, two hundred sixty-one".