61005631 has 2 divisors, whose sum is σ = 61005632. Its totient is φ = 61005630.

The previous prime is 61005629. The next prime is 61005641. The reversal of 61005631 is 13650016.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61005631 - 2¹ = 61005629 is a prime.

It is a super-2 number, since 2×61005631² = 7443374027416322, which contains 22 as substring.

Together with 61005629, 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 (61005641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30502815 + 30502816.

It is an arithmetic number, because the mean of its divisors is an integer number (30502816).

Almost surely, 2^61005631 is an apocalyptic number.

61005631 is a deficient number, since it is larger than the sum of its proper divisors (1).

61005631 is an equidigital number, since it uses as much as digits as its factorization.

61005631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 61005631 is about 7810.6101554232. The cubic root of 61005631 is about 393.6618307330.

Adding to 61005631 its reverse (13650016), we get a palindrome (74655647).

The spelling of 61005631 in words is "sixty-one million, five thousand, six hundred thirty-one".