21594949 has 4 divisors (see below), whose sum is σ = 22054464. Its totient is φ = 21135436.

The previous prime is 21594931. The next prime is 21594959. The reversal of 21594949 is 94949512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21594949 - 2⁵ = 21594917 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 (21594959) 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, 229687 + ... + 229780.

It is an arithmetic number, because the mean of its divisors is an integer number (5513616).

Almost surely, 2^21594949 is an apocalyptic number.

It is an amenable number.

21594949 is a deficient number, since it is larger than the sum of its proper divisors (459515).

21594949 is an equidigital number, since it uses as much as digits as its factorization.

21594949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459514.

The product of its digits is 116640, while the sum is 43.

The square root of 21594949 is about 4647.0365825976. The cubic root of 21594949 is about 278.4736203011.

It can be divided in two parts, 2 and 1594949, that added together give a palindrome (1594951).

The spelling of 21594949 in words is "twenty-one million, five hundred ninety-four thousand, nine hundred forty-nine".