21428599 has 6 divisors (see below), whose sum is σ = 22616160. Its totient is φ = 20300436.

The previous prime is 21428591. The next prime is 21428611. The reversal of 21428599 is 99582412.

It is not a de Polignac number, because 21428599 - 2³ = 21428591 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 (21428591) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 29319 + ... + 30040.

It is an arithmetic number, because the mean of its divisors is an integer number (3769360).

Almost surely, 2^21428599 is an apocalyptic number.

21428599 is a deficient number, since it is larger than the sum of its proper divisors (1187561).

21428599 is an equidigital number, since it uses as much as digits as its factorization.

21428599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59397 (or 59378 counting only the distinct ones).

The product of its digits is 51840, while the sum is 40.

The square root of 21428599 is about 4629.1034769165. The cubic root of 21428599 is about 277.7567312706.

The spelling of 21428599 in words is "twenty-one million, four hundred twenty-eight thousand, five hundred ninety-nine".