646640449 has 16 divisors (see below), whose sum is σ = 796684672. Its totient is φ = 511100928.

The previous prime is 646640431. The next prime is 646640503. The reversal of 646640449 is 944046646.

It is not a de Polignac number, because 646640449 - 2¹³ = 646632257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646610449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101842 + ... + 108004.

It is an arithmetic number, because the mean of its divisors is an integer number (49792792).

Almost surely, 2^646640449 is an apocalyptic number.

It is an amenable number.

646640449 is a deficient number, since it is larger than the sum of its proper divisors (150044223).

646640449 is a wasteful number, since it uses less digits than its factorization.

646640449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7336.

The product of its (nonzero) digits is 497664, while the sum is 43.

The square root of 646640449 is about 25429.1259975643. The cubic root of 646640449 is about 864.7441296058.

The spelling of 646640449 in words is "six hundred forty-six million, six hundred forty thousand, four hundred forty-nine".