646913971 has 8 divisors (see below), whose sum is σ = 747237744. Its totient is φ = 553509120.

The previous prime is 646913807. The next prime is 646913999. The reversal of 646913971 is 179319646.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 646913971 - 2¹⁵ = 646881203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646913171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1729530 + ... + 1729903.

It is an arithmetic number, because the mean of its divisors is an integer number (93404718).

Almost surely, 2^646913971 is an apocalyptic number.

646913971 is a deficient number, since it is larger than the sum of its proper divisors (100323773).

646913971 is a wasteful number, since it uses less digits than its factorization.

646913971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3459461.

The product of its digits is 244944, while the sum is 46.

The square root of 646913971 is about 25434.5035532444. The cubic root of 646913971 is about 864.8660382609.

The spelling of 646913971 in words is "six hundred forty-six million, nine hundred thirteen thousand, nine hundred seventy-one".