647964091 has 4 divisors (see below), whose sum is σ = 665476672. Its totient is φ = 630451512.

The previous prime is 647964089. The next prime is 647964101. The reversal of 647964091 is 190469746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 190469746 = 2 ⋅95234873.

It is a cyclic number.

It is not a de Polignac number, because 647964091 - 2¹ = 647964089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (647964071) 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, 8756235 + ... + 8756308.

It is an arithmetic number, because the mean of its divisors is an integer number (166369168).

Almost surely, 2^647964091 is an apocalyptic number.

647964091 is a deficient number, since it is larger than the sum of its proper divisors (17512581).

647964091 is a wasteful number, since it uses less digits than its factorization.

647964091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17512580.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 647964091 is about 25455.1387935717. The cubic root of 647964091 is about 865.3337574016. Note that the first 3 decimals are identical.

The spelling of 647964091 in words is "six hundred forty-seven million, nine hundred sixty-four thousand, ninety-one".