664101261 has 24 divisors (see below), whose sum is σ = 995991360. Its totient is φ = 442197792.

The previous prime is 664101257. The next prime is 664101323. The reversal of 664101261 is 162101466.

664101261 is a `hidden beast` number, since 6 + 641 + 0 + 12 + 6 + 1 = 666.

664101261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 664101261 - 2² = 664101257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664103261) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 377961 + ... + 379713.

It is an arithmetic number, because the mean of its divisors is an integer number (41499640).

Almost surely, 2^664101261 is an apocalyptic number.

It is an amenable number.

664101261 is a deficient number, since it is larger than the sum of its proper divisors (331890099).

664101261 is a wasteful number, since it uses less digits than its factorization.

664101261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3327 (or 3315 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 664101261 is about 25770.1622230051. The cubic root of 664101261 is about 872.4584801932.

The spelling of 664101261 in words is "six hundred sixty-four million, one hundred one thousand, two hundred sixty-one".