661547371 has 4 divisors (see below), whose sum is σ = 661841200. Its totient is φ = 661253544.

The previous prime is 661547357. The next prime is 661547387. The reversal of 661547371 is 173745166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661547371 - 2¹⁵ = 661514603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661547311) 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, 143511 + ... + 148048.

It is an arithmetic number, because the mean of its divisors is an integer number (165460300).

Almost surely, 2^661547371 is an apocalyptic number.

661547371 is a deficient number, since it is larger than the sum of its proper divisors (293829).

661547371 is a wasteful number, since it uses less digits than its factorization.

661547371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293828.

The product of its digits is 105840, while the sum is 40.

The square root of 661547371 is about 25720.5631936783. The cubic root of 661547371 is about 871.3386583279.

The spelling of 661547371 in words is "six hundred sixty-one million, five hundred forty-seven thousand, three hundred seventy-one".