121565635554 has 96 divisors (see below), whose sum is σ = 270427465728. Its totient is φ = 36400672000.

The previous prime is 121565635507. The next prime is 121565635577. The reversal of 121565635554 is 455536565121.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45240799 + ... + 45243485.

It is an arithmetic number, because the mean of its divisors is an integer number (2816952768).

Almost surely, 2^121565635554 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121565635554, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135213732864).

121565635554 is an abundant number, since it is smaller than the sum of its proper divisors (148861830174).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121565635554 is a wasteful number, since it uses less digits than its factorization.

121565635554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3432 (or 3421 counting only the distinct ones).

The product of its digits is 2700000, while the sum is 48.

The spelling of 121565635554 in words is "one hundred twenty-one billion, five hundred sixty-five million, six hundred thirty-five thousand, five hundred fifty-four".