21350121231511 has 2 divisors, whose sum is σ = 21350121231512. Its totient is φ = 21350121231510.

The previous prime is 21350121231499. The next prime is 21350121231539. The reversal of 21350121231511 is 11513212105312.

It is a happy number.

It is an a-pointer prime, because the next prime (21350121231539) can be obtained adding 21350121231511 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21350121231511 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21350121231511.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21350121231911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675060615755 + 10675060615756.

It is an arithmetic number, because the mean of its divisors is an integer number (10675060615756).

Almost surely, 2^{21350121231511} is an apocalyptic number.

21350121231511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21350121231511 is an equidigital number, since it uses as much as digits as its factorization.

21350121231511 is an evil number, because the sum of its binary digits is even.

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

Adding to 21350121231511 its reverse (11513212105312), we get a palindrome (32863333336823).

The spelling of 21350121231511 in words is "twenty-one trillion, three hundred fifty billion, one hundred twenty-one million, two hundred thirty-one thousand, five hundred eleven".