21155315256419 has 2 divisors, whose sum is σ = 21155315256420. Its totient is φ = 21155315256418.

The previous prime is 21155315256407. The next prime is 21155315256421. The reversal of 21155315256419 is 91465251355112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21155315256419 is a prime.

It is a super-2 number, since 2×21155315256419² (a number of 27 digits) contains 22 as substring.

Together with 21155315256421, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21155315253419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577657628209 + 10577657628210.

It is an arithmetic number, because the mean of its divisors is an integer number (10577657628210).

Almost surely, 2^{21155315256419} is an apocalyptic number.

21155315256419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155315256419 is an equidigital number, since it uses as much as digits as its factorization.

21155315256419 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620000, while the sum is 50.

The spelling of 21155315256419 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred fifteen million, two hundred fifty-six thousand, four hundred nineteen".