61855831 has 2 divisors, whose sum is σ = 61855832. Its totient is φ = 61855830.

The previous prime is 61855817. The next prime is 61855847. The reversal of 61855831 is 13855816.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61855831 - 2⁵ = 61855799 is a prime.

It is a super-2 number, since 2×61855831² = 7652287657401122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61855931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30927915 + 30927916.

It is an arithmetic number, because the mean of its divisors is an integer number (30927916).

Almost surely, 2^61855831 is an apocalyptic number.

61855831 is a deficient number, since it is larger than the sum of its proper divisors (1).

61855831 is an equidigital number, since it uses as much as digits as its factorization.

61855831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28800, while the sum is 37.

The square root of 61855831 is about 7864.8478052662. The cubic root of 61855831 is about 395.4821458470.

The spelling of 61855831 in words is "sixty-one million, eight hundred fifty-five thousand, eight hundred thirty-one".