661609290129 has 16 divisors (see below), whose sum is σ = 953909768448. Its totient is φ = 406294898432.

The previous prime is 661609290127. The next prime is 661609290149. The reversal of 661609290129 is 921092906166.

It is a cyclic number.

It is not a de Polignac number, because 661609290129 - 2¹ = 661609290127 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (661609290127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138005382 + ... + 138010175.

It is an arithmetic number, because the mean of its divisors is an integer number (59619360528).

Almost surely, 2^661609290129 is an apocalyptic number.

It is an amenable number.

661609290129 is a deficient number, since it is larger than the sum of its proper divisors (292300478319).

661609290129 is a wasteful number, since it uses less digits than its factorization.

661609290129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276015624.

The product of its (nonzero) digits is 629856, while the sum is 51.

The spelling of 661609290129 in words is "six hundred sixty-one billion, six hundred nine million, two hundred ninety thousand, one hundred twenty-nine".