21102919 has 2 divisors, whose sum is σ = 21102920. Its totient is φ = 21102918.

The previous prime is 21102911. The next prime is 21102931. The reversal of 21102919 is 91920112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21102919 - 2³ = 21102911 is a prime.

It is a super-2 number, since 2×21102919² = 890666380641122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21102893 and 21102902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551459 + 10551460.

It is an arithmetic number, because the mean of its divisors is an integer number (10551460).

Almost surely, 2^21102919 is an apocalyptic number.

21102919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102919 is an equidigital number, since it uses as much as digits as its factorization.

21102919 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 21102919 is about 4593.7913535554. The cubic root of 21102919 is about 276.3423908326.

The spelling of 21102919 in words is "twenty-one million, one hundred two thousand, nine hundred nineteen".