612665891 has 4 divisors (see below), whose sum is σ = 612745392. Its totient is φ = 612586392.

The previous prime is 612665827. The next prime is 612665897. The reversal of 612665891 is 198566216.

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 612665891 - 2⁶ = 612665827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (612665897) 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, 26780 + ... + 44073.

It is an arithmetic number, because the mean of its divisors is an integer number (153186348).

Almost surely, 2^612665891 is an apocalyptic number.

612665891 is a deficient number, since it is larger than the sum of its proper divisors (79501).

612665891 is an equidigital number, since it uses as much as digits as its factorization.

612665891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79500.

The product of its digits is 155520, while the sum is 44.

The square root of 612665891 is about 24752.0886189428. The cubic root of 612665891 is about 849.3262901495.

The spelling of 612665891 in words is "six hundred twelve million, six hundred sixty-five thousand, eight hundred ninety-one".