664140061 has 8 divisors (see below), whose sum is σ = 716607864. Its totient is φ = 611869440.

The previous prime is 664139981. The next prime is 664140073. The reversal of 664140061 is 160041466.

It can be written as a sum of positive squares in 4 ways, for example, as 9036036 + 655104025 = 3006^2 + 25595^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 664140061 - 2¹⁵ = 664107293 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 (664140661) 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, 42256 + ... + 55801.

It is an arithmetic number, because the mean of its divisors is an integer number (89575983).

Almost surely, 2^664140061 is an apocalyptic number.

It is an amenable number.

664140061 is a deficient number, since it is larger than the sum of its proper divisors (52467803).

664140061 is a wasteful number, since it uses less digits than its factorization.

664140061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98591.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 664140061 is about 25770.9150206197. The cubic root of 664140061 is about 872.4754709404.

The spelling of 664140061 in words is "six hundred sixty-four million, one hundred forty thousand, sixty-one".