121557065557 has 32 divisors (see below), whose sum is σ = 133510809600. Its totient is φ = 110216294400.

The previous prime is 121557065537. The next prime is 121557065569. The reversal of 121557065557 is 755560755121.

It is a cyclic number.

It is not a de Polignac number, because 121557065557 - 2¹⁹ = 121556541269 is a prime.

It is a super-2 number, since 2×121557065557² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121557065557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121557065537) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18501369 + ... + 18507937.

It is an arithmetic number, because the mean of its divisors is an integer number (4172212800).

Almost surely, 2^121557065557 is an apocalyptic number.

121557065557 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

121557065557 is a deficient number, since it is larger than the sum of its proper divisors (11953744043).

121557065557 is a wasteful number, since it uses less digits than its factorization.

121557065557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6957.

The product of its (nonzero) digits is 1837500, while the sum is 49.

The spelling of 121557065557 in words is "one hundred twenty-one billion, five hundred fifty-seven million, sixty-five thousand, five hundred fifty-seven".