1861230561 has 4 divisors (see below), whose sum is σ = 2481640752. Its totient is φ = 1240820372.

The previous prime is 1861230559. The next prime is 1861230563. The reversal of 1861230561 is 1650321681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1650321681 = 3 ⋅550107227.

It is an interprime number because it is at equal distance from previous prime (1861230559) and next prime (1861230563).

It is a cyclic number.

It is not a de Polignac number, because 1861230561 - 2¹ = 1861230559 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1861230563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 310205091 + ... + 310205096.

It is an arithmetic number, because the mean of its divisors is an integer number (620410188).

Almost surely, 2^1861230561 is an apocalyptic number.

It is an amenable number.

1861230561 is a deficient number, since it is larger than the sum of its proper divisors (620410191).

1861230561 is an equidigital number, since it uses as much as digits as its factorization.

1861230561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620410190.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 1861230561 is about 43141.9814218123. The cubic root of 1861230561 is about 1230.0800972362.

The spelling of 1861230561 in words is "one billion, eight hundred sixty-one million, two hundred thirty thousand, five hundred sixty-one".