1861619749 has 4 divisors (see below), whose sum is σ = 2030857920. Its totient is φ = 1692381580.

The previous prime is 1861619717. The next prime is 1861619783. The reversal of 1861619749 is 9479161681.

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: 9479161681 = 11 ⋅861741971.

It is a cyclic number.

It is not a de Polignac number, because 1861619749 - 2⁵ = 1861619717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1861619696 and 1861619705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861619549) 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, 84619069 + ... + 84619090.

It is an arithmetic number, because the mean of its divisors is an integer number (507714480).

Almost surely, 2^1861619749 is an apocalyptic number.

It is an amenable number.

1861619749 is a deficient number, since it is larger than the sum of its proper divisors (169238171).

1861619749 is a wasteful number, since it uses less digits than its factorization.

1861619749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169238170.

The product of its digits is 653184, while the sum is 52.

The square root of 1861619749 is about 43146.4917345547. The cubic root of 1861619749 is about 1230.1658288768.

The spelling of 1861619749 in words is "one billion, eight hundred sixty-one million, six hundred nineteen thousand, seven hundred forty-nine".