61555121 has 4 divisors (see below), whose sum is σ = 61612032. Its totient is φ = 61498212.

The previous prime is 61555103. The next prime is 61555127. The reversal of 61555121 is 12155516.

61555121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61555121 - 2¹⁸ = 61292977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61555127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26801 + ... + 29006.

It is an arithmetic number, because the mean of its divisors is an integer number (15403008).

Almost surely, 2^61555121 is an apocalyptic number.

It is an amenable number.

61555121 is a deficient number, since it is larger than the sum of its proper divisors (56911).

61555121 is a wasteful number, since it uses less digits than its factorization.

61555121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56910.

The product of its digits is 1500, while the sum is 26.

The square root of 61555121 is about 7845.7071701664. The cubic root of 61555121 is about 394.8402302095.

The spelling of 61555121 in words is "sixty-one million, five hundred fifty-five thousand, one hundred twenty-one".