129735661 has 4 divisors (see below), whose sum is σ = 141529824. Its totient is φ = 117941500.

The previous prime is 129735659. The next prime is 129735689. The reversal of 129735661 is 166537921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 129735661 - 2¹ = 129735659 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 (129735761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5897065 + ... + 5897086.

It is an arithmetic number, because the mean of its divisors is an integer number (35382456).

Almost surely, 2^129735661 is an apocalyptic number.

129735661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129735661 is a deficient number, since it is larger than the sum of its proper divisors (11794163).

129735661 is a wasteful number, since it uses less digits than its factorization.

129735661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11794162.

The product of its digits is 68040, while the sum is 40.

The square root of 129735661 is about 11390.1563202618. The cubic root of 129735661 is about 506.2361130977.

The spelling of 129735661 in words is "one hundred twenty-nine million, seven hundred thirty-five thousand, six hundred sixty-one".