21457659 has 8 divisors (see below), whose sum is σ = 28730880. Its totient is φ = 14244776.

The previous prime is 21457649. The next prime is 21457679. The reversal of 21457659 is 95675412.

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

It is a cyclic number.

It is not a de Polignac number, because 21457659 - 2⁵ = 21457627 is a prime.

It is a super-2 number, since 2×21457659² = 920862259520562, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21457649) 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, 14247 + ... + 15680.

It is an arithmetic number, because the mean of its divisors is an integer number (3591360).

Almost surely, 2^21457659 is an apocalyptic number.

21457659 is a deficient number, since it is larger than the sum of its proper divisors (7273221).

21457659 is a wasteful number, since it uses less digits than its factorization.

21457659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30169.

The product of its digits is 75600, while the sum is 39.

The square root of 21457659 is about 4632.2412501941. The cubic root of 21457659 is about 277.8822327812.

The spelling of 21457659 in words is "twenty-one million, four hundred fifty-seven thousand, six hundred fifty-nine".