661642135 has 16 divisors (see below), whose sum is σ = 989885952. Its totient is φ = 412452000.

The previous prime is 661642129. The next prime is 661642139. The reversal of 661642135 is 531246166.

It is not a de Polignac number, because 661642135 - 2²⁹ = 124771223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661642135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661642139) 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, 858891 + ... + 859660.

It is an arithmetic number, because the mean of its divisors is an integer number (61867872).

Almost surely, 2^661642135 is an apocalyptic number.

661642135 is a deficient number, since it is larger than the sum of its proper divisors (328243817).

661642135 is a wasteful number, since it uses less digits than its factorization.

661642135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1718574.

The product of its digits is 25920, while the sum is 34.

The square root of 661642135 is about 25722.4053113234. The cubic root of 661642135 is about 871.3802615941.

The spelling of 661642135 in words is "six hundred sixty-one million, six hundred forty-two thousand, one hundred thirty-five".