21159137 has 8 divisors (see below), whose sum is σ = 21755304. Its totient is φ = 20570368.

The previous prime is 21159133. The next prime is 21159161. The reversal of 21159137 is 73195112.

It can be written as a sum of positive squares in 4 ways, for example, as 2531281 + 18627856 = 1591^2 + 4316^2 .

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 21159137 - 2² = 21159133 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21159133) 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, 4223 + ... + 7755.

It is an arithmetic number, because the mean of its divisors is an integer number (2719413).

Almost surely, 2^21159137 is an apocalyptic number.

It is an amenable number.

21159137 is a deficient number, since it is larger than the sum of its proper divisors (596167).

21159137 is a wasteful number, since it uses less digits than its factorization.

21159137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3699.

The product of its digits is 1890, while the sum is 29.

The square root of 21159137 is about 4599.9061946957. The cubic root of 21159137 is about 276.5875645216.

The spelling of 21159137 in words is "twenty-one million, one hundred fifty-nine thousand, one hundred thirty-seven".