21155419 has 2 divisors, whose sum is σ = 21155420. Its totient is φ = 21155418.

The previous prime is 21155411. The next prime is 21155437. The reversal of 21155419 is 91455112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21155419 - 2³ = 21155411 is a prime.

It is a super-2 number, since 2×21155419² = 895103506131122, which contains 22 as substring.

It is equal to p_1339165 and since 21155419 and 1339165 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21155411) 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, 10577709 + 10577710.

It is an arithmetic number, because the mean of its divisors is an integer number (10577710).

Almost surely, 2^21155419 is an apocalyptic number.

21155419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155419 is an equidigital number, since it uses as much as digits as its factorization.

21155419 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The square root of 21155419 is about 4599.5020382646. The cubic root of 21155419 is about 276.5713632811.

The spelling of 21155419 in words is "twenty-one million, one hundred fifty-five thousand, four hundred nineteen".