21159457 has 8 divisors (see below), whose sum is σ = 23218560. Its totient is φ = 19122960.

The previous prime is 21159431. The next prime is 21159461. The reversal of 21159457 is 75495112.

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 21159457 - 2¹⁹ = 20635169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21159427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3657 + ... + 7462.

It is an arithmetic number, because the mean of its divisors is an integer number (2902320).

Almost surely, 2^21159457 is an apocalyptic number.

It is an amenable number.

21159457 is a deficient number, since it is larger than the sum of its proper divisors (2059103).

21159457 is a wasteful number, since it uses less digits than its factorization.

21159457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11303.

The product of its digits is 12600, while the sum is 34.

The square root of 21159457 is about 4599.9409778822. The cubic root of 21159457 is about 276.5889588377.

The spelling of 21159457 in words is "twenty-one million, one hundred fifty-nine thousand, four hundred fifty-seven".