21156459 has 8 divisors (see below), whose sum is σ = 28396032. Its totient is φ = 14010600.

The previous prime is 21156419. The next prime is 21156463. The reversal of 21156459 is 95465112.

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

It is not a de Polignac number, because 21156459 - 2²¹ = 19059307 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21156419) 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, 22899 + ... + 23804.

It is an arithmetic number, because the mean of its divisors is an integer number (3549504).

Almost surely, 2^21156459 is an apocalyptic number.

21156459 is a deficient number, since it is larger than the sum of its proper divisors (7239573).

21156459 is a wasteful number, since it uses less digits than its factorization.

21156459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46857.

The product of its digits is 10800, while the sum is 33.

The square root of 21156459 is about 4599.6150925920. The cubic root of 21156459 is about 276.5758952879.

The spelling of 21156459 in words is "twenty-one million, one hundred fifty-six thousand, four hundred fifty-nine".