15121109491 has 2 divisors, whose sum is σ = 15121109492. Its totient is φ = 15121109490.

The previous prime is 15121109453. The next prime is 15121109503. The reversal of 15121109491 is 19490112151.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15121109491 - 2⁷ = 15121109363 is a prime.

It is not a weakly prime, because it can be changed into another prime (15121109431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7560554745 + 7560554746.

It is an arithmetic number, because the mean of its divisors is an integer number (7560554746).

Almost surely, 2^15121109491 is an apocalyptic number.

15121109491 is a deficient number, since it is larger than the sum of its proper divisors (1).

15121109491 is an equidigital number, since it uses as much as digits as its factorization.

15121109491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 34.

The spelling of 15121109491 in words is "fifteen billion, one hundred twenty-one million, one hundred nine thousand, four hundred ninety-one".