21428064391 has 8 divisors (see below), whose sum is σ = 21462835968. Its totient is φ = 21393315000.

The previous prime is 21428064349. The next prime is 21428064401. The reversal of 21428064391 is 19346082412.

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 21428064391 - 2³¹ = 19280580743 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 (21428064331) 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, 4093746 + ... + 4098976.

It is an arithmetic number, because the mean of its divisors is an integer number (2682854496).

Almost surely, 2^21428064391 is an apocalyptic number.

21428064391 is a deficient number, since it is larger than the sum of its proper divisors (34771577).

21428064391 is an equidigital number, since it uses as much as digits as its factorization.

21428064391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11093.

The product of its (nonzero) digits is 82944, while the sum is 40.

The spelling of 21428064391 in words is "twenty-one billion, four hundred twenty-eight million, sixty-four thousand, three hundred ninety-one".