21079237 has 2 divisors, whose sum is σ = 21079238. Its totient is φ = 21079236.

The previous prime is 21079181. The next prime is 21079243. The reversal of 21079237 is 73297012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17715681 + 3363556 = 4209^2 + 1834^2 .

It is a cyclic number.

It is not a de Polignac number, because 21079237 - 2¹⁹ = 20554949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21079199 and 21079208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21079297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10539618 + 10539619.

It is an arithmetic number, because the mean of its divisors is an integer number (10539619).

Almost surely, 2^21079237 is an apocalyptic number.

It is an amenable number.

21079237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079237 is an equidigital number, since it uses as much as digits as its factorization.

21079237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 21079237 is about 4591.2130205426. The cubic root of 21079237 is about 276.2389803348.

It can be divided in two parts, 21079 and 237, that added together give a square (21316 = 146²).

The spelling of 21079237 in words is "twenty-one million, seventy-nine thousand, two hundred thirty-seven".