21012159 has 8 divisors (see below), whose sum is σ = 32018560. Its totient is φ = 12006936.

The previous prime is 21012151. The next prime is 21012161. The reversal of 21012159 is 95121012.

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

It is not a de Polignac number, because 21012159 - 2³ = 21012151 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1000579 = 21012159 / (2 + 1 + 0 + 1 + 2 + 1 + 5 + 9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012151) 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, 500269 + ... + 500310.

It is an arithmetic number, because the mean of its divisors is an integer number (4002320).

Almost surely, 2^21012159 is an apocalyptic number.

21012159 is a deficient number, since it is larger than the sum of its proper divisors (11006401).

21012159 is a wasteful number, since it uses less digits than its factorization.

21012159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000589.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 21012159 is about 4583.9021586417. The cubic root of 21012159 is about 275.9456546013.

The spelling of 21012159 in words is "twenty-one million, twelve thousand, one hundred fifty-nine".