121577778 has 96 divisors (see below), whose sum is σ = 321459840. Its totient is φ = 32417280.

The previous prime is 121577759. The next prime is 121577783. The reversal of 121577778 is 877775121.

It is a happy number.

121577778 is a `hidden beast` number, since 1 + 2 + 1 + 577 + 7 + 78 = 666.

It is a super-2 number, since 2×121577778² = 29562312206834568, which contains 22 as substring.

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, 451828 + ... + 452096.

It is an arithmetic number, because the mean of its divisors is an integer number (3348540).

Almost surely, 2^121577778 is an apocalyptic number.

121577778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 121577778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160729920).

121577778 is an abundant number, since it is smaller than the sum of its proper divisors (199882062).

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

121577778 is a wasteful number, since it uses less digits than its factorization.

121577778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512 (or 509 counting only the distinct ones).

The product of its digits is 192080, while the sum is 45.

The square root of 121577778 is about 11026.2313598074. The cubic root of 121577778 is about 495.3947509213.

The spelling of 121577778 in words is "one hundred twenty-one million, five hundred seventy-seven thousand, seven hundred seventy-eight".