1858861681 has 4 divisors (see below), whose sum is σ = 1867671664. Its totient is φ = 1850051700.

The previous prime is 1858861661. The next prime is 1858861757. The reversal of 1858861681 is 1861688581.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1858861681 - 2⁷ = 1858861553 is a prime.

It is a super-2 number, since 2×1858861681² = 6910733498180291522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1858861661) 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, 4404675 + ... + 4405096.

It is an arithmetic number, because the mean of its divisors is an integer number (466917916).

Almost surely, 2^1858861681 is an apocalyptic number.

It is an amenable number.

1858861681 is a deficient number, since it is larger than the sum of its proper divisors (8809983).

1858861681 is an equidigital number, since it uses as much as digits as its factorization.

1858861681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8809982.

The product of its digits is 737280, while the sum is 52.

The square root of 1858861681 is about 43114.5182160256. The cubic root of 1858861681 is about 1229.5580144624.

The spelling of 1858861681 in words is "one billion, eight hundred fifty-eight million, eight hundred sixty-one thousand, six hundred eighty-one".