21428388347 has 16 divisors (see below), whose sum is σ = 23964669600. Its totient is φ = 19070795520.

The previous prime is 21428388337. The next prime is 21428388353. The reversal of 21428388347 is 74388382412.

It is not a de Polignac number, because 21428388347 - 2²⁴ = 21411611131 is a prime.

It is a super-4 number, since 4×21428388347⁴ (a number of 42 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21428388295 and 21428388304.

It is not an unprimeable number, because it can be changed into a prime (21428388337) 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, 505154 + ... + 545927.

It is an arithmetic number, because the mean of its divisors is an integer number (1497791850).

Almost surely, 2^21428388347 is an apocalyptic number.

21428388347 is a deficient number, since it is larger than the sum of its proper divisors (2536281253).

21428388347 is a wasteful number, since it uses less digits than its factorization.

21428388347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051166.

The product of its digits is 2064384, while the sum is 50.

The spelling of 21428388347 in words is "twenty-one billion, four hundred twenty-eight million, three hundred eighty-eight thousand, three hundred forty-seven".