21155315256407 has 2 divisors, whose sum is σ = 21155315256408. Its totient is φ = 21155315256406.

The previous prime is 21155315256377. The next prime is 21155315256419. The reversal of 21155315256407 is 70465251355112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21155315256407 - 2¹² = 21155315252311 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21155315256487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577657628203 + 10577657628204.

It is an arithmetic number, because the mean of its divisors is an integer number (10577657628204).

Almost surely, 2^{21155315256407} is an apocalyptic number.

21155315256407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155315256407 is an equidigital number, since it uses as much as digits as its factorization.

21155315256407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260000, while the sum is 47.

The spelling of 21155315256407 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred fifteen million, two hundred fifty-six thousand, four hundred seven".