661628297 has 4 divisors (see below), whose sum is σ = 721776336. Its totient is φ = 601480260.

The previous prime is 661628249. The next prime is 661628299. The reversal of 661628297 is 792826166.

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 661628297 - 2⁸ = 661628041 is a prime.

It is a super-2 number, since 2×661628297² = 875504006782240418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661628299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30074003 + ... + 30074024.

It is an arithmetic number, because the mean of its divisors is an integer number (180444084).

Almost surely, 2^661628297 is an apocalyptic number.

It is an amenable number.

661628297 is a deficient number, since it is larger than the sum of its proper divisors (60148039).

661628297 is a wasteful number, since it uses less digits than its factorization.

661628297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60148038.

The product of its digits is 435456, while the sum is 47.

The square root of 661628297 is about 25722.1363226307. The cubic root of 661628297 is about 871.3741866867.

The spelling of 661628297 in words is "six hundred sixty-one million, six hundred twenty-eight thousand, two hundred ninety-seven".