1861002581 has 2 divisors, whose sum is σ = 1861002582. Its totient is φ = 1861002580.

The previous prime is 1861002527. The next prime is 1861002593. The reversal of 1861002581 is 1852001681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1097861956 + 763140625 = 33134^2 + 27625^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861002581 - 2¹⁸ = 1860740437 is a prime.

It is a super-2 number, since 2×1861002581² = 6926661212977323122, which contains 22 as substring.

It is a Sophie Germain 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 (1861002281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930501290 + 930501291.

It is an arithmetic number, because the mean of its divisors is an integer number (930501291).

Almost surely, 2^1861002581 is an apocalyptic number.

It is an amenable number.

1861002581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861002581 is an equidigital number, since it uses as much as digits as its factorization.

1861002581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 32.

The square root of 1861002581 is about 43139.3391349474. The cubic root of 1861002581 is about 1230.0298714846.

The spelling of 1861002581 in words is "one billion, eight hundred sixty-one million, two thousand, five hundred eighty-one".