21428801643 has 8 divisors (see below), whose sum is σ = 28572415488. Its totient is φ = 14285527784.

The previous prime is 21428801633. The next prime is 21428801651. The reversal of 21428801643 is 34610882412.

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

It is a cyclic number.

It is not a de Polignac number, because 21428801643 - 2⁴ = 21428801627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21428801623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180946 + ... + 274952.

It is an arithmetic number, because the mean of its divisors is an integer number (3571551936).

Almost surely, 2^21428801643 is an apocalyptic number.

21428801643 is a deficient number, since it is larger than the sum of its proper divisors (7143613845).

21428801643 is an equidigital number, since it uses as much as digits as its factorization.

21428801643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169993.

The product of its (nonzero) digits is 73728, while the sum is 39.

The spelling of 21428801643 in words is "twenty-one billion, four hundred twenty-eight million, eight hundred one thousand, six hundred forty-three".