646432421 has 16 divisors (see below), whose sum is σ = 690662400. Its totient is φ = 603288000.

The previous prime is 646432403. The next prime is 646432453. The reversal of 646432421 is 124234646.

646432421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-646432421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646492421) 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, 438716 + ... + 440186.

It is an arithmetic number, because the mean of its divisors is an integer number (43166400).

Almost surely, 2^646432421 is an apocalyptic number.

It is an amenable number.

646432421 is a deficient number, since it is larger than the sum of its proper divisors (44229979).

646432421 is a wasteful number, since it uses less digits than its factorization.

646432421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1820.

The product of its digits is 27648, while the sum is 32.

The square root of 646432421 is about 25425.0353195428. The cubic root of 646432421 is about 864.6513885851.

The spelling of 646432421 in words is "six hundred forty-six million, four hundred thirty-two thousand, four hundred twenty-one".