75128661 has 16 divisors (see below), whose sum is σ = 117849600. Its totient is φ = 47139264.

The previous prime is 75128629. The next prime is 75128663. The reversal of 75128661 is 16682157.

75128661 is a `hidden beast` number, since 7 + 512 + 86 + 61 = 666.

It is not a de Polignac number, because 75128661 - 2⁵ = 75128629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75128663) 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, 81381 + ... + 82298.

It is an arithmetic number, because the mean of its divisors is an integer number (7365600).

Almost surely, 2^75128661 is an apocalyptic number.

It is an amenable number.

75128661 is a deficient number, since it is larger than the sum of its proper divisors (42720939).

75128661 is a wasteful number, since it uses less digits than its factorization.

75128661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163705 (or 163699 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 75128661 is about 8667.6791011204. The cubic root of 75128661 is about 421.9573435317.

The spelling of 75128661 in words is "seventy-five million, one hundred twenty-eight thousand, six hundred sixty-one".