21959291 has 8 divisors (see below), whose sum is σ = 23478624. Its totient is φ = 20465280.

The previous prime is 21959279. The next prime is 21959297. The reversal of 21959291 is 19295912.

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

It is not a de Polignac number, because 21959291 - 2¹⁰ = 21958267 is a prime.

It is a super-2 number, since 2×21959291² = 964420922445362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21959297) 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, 4520 + ... + 8021.

It is an arithmetic number, because the mean of its divisors is an integer number (2934828).

Almost surely, 2^21959291 is an apocalyptic number.

21959291 is a deficient number, since it is larger than the sum of its proper divisors (1519333).

21959291 is a wasteful number, since it uses less digits than its factorization.

21959291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12661.

The product of its digits is 14580, while the sum is 38.

The square root of 21959291 is about 4686.0741564768. The cubic root of 21959291 is about 280.0309957183.

The spelling of 21959291 in words is "twenty-one million, nine hundred fifty-nine thousand, two hundred ninety-one".