21598847 has 4 divisors (see below), whose sum is σ = 22295616. Its totient is φ = 20902080.

The previous prime is 21598807. The next prime is 21598849. The reversal of 21598847 is 74889512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21598847 - 2⁶ = 21598783 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21598798 and 21598807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21598849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 348338 + ... + 348399.

It is an arithmetic number, because the mean of its divisors is an integer number (5573904).

Almost surely, 2^21598847 is an apocalyptic number.

21598847 is a deficient number, since it is larger than the sum of its proper divisors (696769).

21598847 is an equidigital number, since it uses as much as digits as its factorization.

21598847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696768.

The product of its digits is 161280, while the sum is 44.

The square root of 21598847 is about 4647.4559707436. The cubic root of 21598847 is about 278.4903746027.

The spelling of 21598847 in words is "twenty-one million, five hundred ninety-eight thousand, eight hundred forty-seven".