61541981 has 2 divisors, whose sum is σ = 61541982. Its totient is φ = 61541980.

The previous prime is 61541939. The next prime is 61541999. The reversal of 61541981 is 18914516.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52330756 + 9211225 = 7234^2 + 3035^2 .

It is a cyclic number.

It is not a de Polignac number, because 61541981 - 2²² = 57347677 is a prime.

It is a super-2 number, since 2×61541981² = 7574830850808722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61541911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30770990 + 30770991.

It is an arithmetic number, because the mean of its divisors is an integer number (30770991).

Almost surely, 2^61541981 is an apocalyptic number.

It is an amenable number.

61541981 is a deficient number, since it is larger than the sum of its proper divisors (1).

61541981 is an equidigital number, since it uses as much as digits as its factorization.

61541981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 35.

The square root of 61541981 is about 7844.8697248584. The cubic root of 61541981 is about 394.8121330626.

The spelling of 61541981 in words is "sixty-one million, five hundred forty-one thousand, nine hundred eighty-one".