21151619 has 2 divisors, whose sum is σ = 21151620. Its totient is φ = 21151618.

The previous prime is 21151609. The next prime is 21151639. The reversal of 21151619 is 91615112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21151619 - 2¹² = 21147523 is a prime.

It is a super-2 number, since 2×21151619² = 894781972642322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21151609) 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, 10575809 + 10575810.

It is an arithmetic number, because the mean of its divisors is an integer number (10575810).

Almost surely, 2^21151619 is an apocalyptic number.

21151619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151619 is an equidigital number, since it uses as much as digits as its factorization.

21151619 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 21151619 is about 4599.0889315168. The cubic root of 21151619 is about 276.5548027628.

The spelling of 21151619 in words is "twenty-one million, one hundred fifty-one thousand, six hundred nineteen".