661396901 has 16 divisors (see below), whose sum is σ = 756891648. Its totient is φ = 572074800.

The previous prime is 661396891. The next prime is 661396907. The reversal of 661396901 is 109693166.

It is a de Polignac number, because none of the positive numbers 2^k-661396901 is a prime.

It is a super-3 number, since 3×661396901³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661396907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41480 + ... + 55166.

It is an arithmetic number, because the mean of its divisors is an integer number (47305728).

Almost surely, 2^661396901 is an apocalyptic number.

It is an amenable number.

661396901 is a deficient number, since it is larger than the sum of its proper divisors (95494747).

661396901 is a wasteful number, since it uses less digits than its factorization.

661396901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13912.

The product of its (nonzero) digits is 52488, while the sum is 41.

The square root of 661396901 is about 25717.6379358603. The cubic root of 661396901 is about 871.2725908648.

The spelling of 661396901 in words is "six hundred sixty-one million, three hundred ninety-six thousand, nine hundred one".