661137073 has 4 divisors (see below), whose sum is σ = 662643520. Its totient is φ = 659630628.

The previous prime is 661137049. The next prime is 661137107. The reversal of 661137073 is 370731166.

It is a happy number.

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 661137073 - 2⁹ = 661136561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661137773) 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, 752565 + ... + 753442.

It is an arithmetic number, because the mean of its divisors is an integer number (165660880).

Almost surely, 2^661137073 is an apocalyptic number.

It is an amenable number.

661137073 is a deficient number, since it is larger than the sum of its proper divisors (1506447).

661137073 is a wasteful number, since it uses less digits than its factorization.

661137073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1506446.

The product of its (nonzero) digits is 15876, while the sum is 34.

The square root of 661137073 is about 25712.5858870709. The cubic root of 661137073 is about 871.1584835538.

The spelling of 661137073 in words is "six hundred sixty-one million, one hundred thirty-seven thousand, seventy-three".