121521977399 has 2 divisors, whose sum is σ = 121521977400. Its totient is φ = 121521977398.

The previous prime is 121521977327. The next prime is 121521977411. The reversal of 121521977399 is 993779125121.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (993779125121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121521977399 - 2²⁸ = 121253541943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121521977309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60760988699 + 60760988700.

It is an arithmetic number, because the mean of its divisors is an integer number (60760988700).

Almost surely, 2^121521977399 is an apocalyptic number.

121521977399 is a deficient number, since it is larger than the sum of its proper divisors (1).

121521977399 is an equidigital number, since it uses as much as digits as its factorization.

121521977399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2143260, while the sum is 56.

The spelling of 121521977399 in words is "one hundred twenty-one billion, five hundred twenty-one million, nine hundred seventy-seven thousand, three hundred ninety-nine".