121621777 has 4 divisors (see below), whose sum is σ = 122396596. Its totient is φ = 120846960.

The previous prime is 121621763. The next prime is 121621781. The reversal of 121621777 is 777126121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 777126121 = 53 ⋅14662757.

It can be written as a sum of positive squares in 2 ways, for example, as 54774801 + 66846976 = 7401^2 + 8176^2 .

It is a cyclic number.

It is not a de Polignac number, because 121621777 - 2¹⁵ = 121589009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121621177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 387174 + ... + 387487.

It is an arithmetic number, because the mean of its divisors is an integer number (30599149).

Almost surely, 2^121621777 is an apocalyptic number.

It is an amenable number.

121621777 is a deficient number, since it is larger than the sum of its proper divisors (774819).

121621777 is an equidigital number, since it uses as much as digits as its factorization.

121621777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 774818.

The product of its digits is 8232, while the sum is 34.

The square root of 121621777 is about 11028.2263759863. The cubic root of 121621777 is about 495.4545048366.

Adding to 121621777 its reverse (777126121), we get a palindrome (898747898).

The spelling of 121621777 in words is "one hundred twenty-one million, six hundred twenty-one thousand, seven hundred seventy-seven".