61643831 has 2 divisors, whose sum is σ = 61643832. Its totient is φ = 61643830.

The previous prime is 61643797. The next prime is 61643863. The reversal of 61643831 is 13834616.

It is an a-pointer prime, because the next prime (61643863) can be obtained adding 61643831 to its sum of digits (32).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61643831 is a prime.

It is a super-2 number, since 2×61643831² = 7599923800713122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61643891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30821915 + 30821916.

It is an arithmetic number, because the mean of its divisors is an integer number (30821916).

Almost surely, 2^61643831 is an apocalyptic number.

61643831 is a deficient number, since it is larger than the sum of its proper divisors (1).

61643831 is an equidigital number, since it uses as much as digits as its factorization.

61643831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 32.

The square root of 61643831 is about 7851.3585448634. The cubic root of 61643831 is about 395.0298134844.

The spelling of 61643831 in words is "sixty-one million, six hundred forty-three thousand, eight hundred thirty-one".