21585949 has 8 divisors (see below), whose sum is σ = 26912448. Its totient is φ = 16820160.

The previous prime is 21585943. The next prime is 21585953. The reversal of 21585949 is 94958512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21585949 - 2¹³ = 21577757 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 (21585943) 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, 140092 + ... + 140245.

It is an arithmetic number, because the mean of its divisors is an integer number (3364056).

Almost surely, 2^21585949 is an apocalyptic number.

It is an amenable number.

21585949 is a deficient number, since it is larger than the sum of its proper divisors (5326499).

21585949 is a wasteful number, since it uses less digits than its factorization.

21585949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280355.

The product of its digits is 129600, while the sum is 43.

The square root of 21585949 is about 4646.0681226172. The cubic root of 21585949 is about 278.4349289875.

The spelling of 21585949 in words is "twenty-one million, five hundred eighty-five thousand, nine hundred forty-nine".