61555831 has 2 divisors, whose sum is σ = 61555832. Its totient is φ = 61555830.

The previous prime is 61555829. The next prime is 61555841. The reversal of 61555831 is 13855516.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61555831 - 2¹ = 61555829 is a prime.

It is a super-2 number, since 2×61555831² = 7578240660201122, which contains 22 as substring.

Together with 61555829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61555841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30777915 + 30777916.

It is an arithmetic number, because the mean of its divisors is an integer number (30777916).

Almost surely, 2^61555831 is an apocalyptic number.

61555831 is a deficient number, since it is larger than the sum of its proper divisors (1).

61555831 is an equidigital number, since it uses as much as digits as its factorization.

61555831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18000, while the sum is 34.

The square root of 61555831 is about 7845.7524177099. The cubic root of 61555831 is about 394.8417482824.

The spelling of 61555831 in words is "sixty-one million, five hundred fifty-five thousand, eight hundred thirty-one".