1861144451 has 4 divisors (see below), whose sum is σ = 1865384400. Its totient is φ = 1856904504.

The previous prime is 1861144433. The next prime is 1861144459. The reversal of 1861144451 is 1544411681.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1861144451 - 2⁶ = 1861144387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1861144459) 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, 2119316 + ... + 2120193.

It is an arithmetic number, because the mean of its divisors is an integer number (466346100).

Almost surely, 2^1861144451 is an apocalyptic number.

1861144451 is a deficient number, since it is larger than the sum of its proper divisors (4239949).

1861144451 is an equidigital number, since it uses as much as digits as its factorization.

1861144451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4239948.

The product of its digits is 15360, while the sum is 35.

The square root of 1861144451 is about 43140.9834264357. The cubic root of 1861144451 is about 1230.0611270214.

The spelling of 1861144451 in words is "one billion, eight hundred sixty-one million, one hundred forty-four thousand, four hundred fifty-one".