101561381 has 2 divisors, whose sum is σ = 101561382. Its totient is φ = 101561380.

The previous prime is 101561359. The next prime is 101561423. The reversal of 101561381 is 183165101.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 88529281 + 13032100 = 9409^2 + 3610^2 .

It is a cyclic number.

It is not a de Polignac number, because 101561381 - 2¹⁰ = 101560357 is a prime.

It is a super-2 number, since 2×101561381² = 20629428221254322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 101561381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101561321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50780690 + 50780691.

It is an arithmetic number, because the mean of its divisors is an integer number (50780691).

Almost surely, 2^101561381 is an apocalyptic number.

It is an amenable number.

101561381 is a deficient number, since it is larger than the sum of its proper divisors (1).

101561381 is an equidigital number, since it uses as much as digits as its factorization.

101561381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 101561381 is about 10077.7666672731. The cubic root of 101561381 is about 466.5621810861.

The spelling of 101561381 in words is "one hundred one million, five hundred sixty-one thousand, three hundred eighty-one".