21161519 has 2 divisors, whose sum is σ = 21161520. Its totient is φ = 21161518.

The previous prime is 21161509. The next prime is 21161527. The reversal of 21161519 is 91516112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21161519 - 2¹⁶ = 21095983 is a prime.

It is a super-2 number, since 2×21161519² = 895619772774722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21161509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10580759 + 10580760.

It is an arithmetic number, because the mean of its divisors is an integer number (10580760).

Almost surely, 2^21161519 is an apocalyptic number.

21161519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161519 is an equidigital number, since it uses as much as digits as its factorization.

21161519 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 26.

The square root of 21161519 is about 4600.1651057326. The cubic root of 21161519 is about 276.5979431248.

The spelling of 21161519 in words is "twenty-one million, one hundred sixty-one thousand, five hundred nineteen".