1861438658644 has 12 divisors (see below), whose sum is σ = 3257543356564. Its totient is φ = 930711985344.

The previous prime is 1861438658627. The next prime is 1861438658659. The reversal of 1861438658644 is 4468568341681.

It can be written as a sum of positive squares in 2 ways, for example, as 1480144758544 + 381293900100 = 1216612^2 + 617490^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1244529 + ... + 2296024.

Almost surely, 2^{1861438658644} is an apocalyptic number.

It is an amenable number.

1861438658644 is a deficient number, since it is larger than the sum of its proper divisors (1396104697920).

1861438658644 is a wasteful number, since it uses less digits than its factorization.

1861438658644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3671994 (or 3671992 counting only the distinct ones).

The product of its digits is 106168320, while the sum is 64.

The spelling of 1861438658644 in words is "one trillion, eight hundred sixty-one billion, four hundred thirty-eight million, six hundred fifty-eight thousand, six hundred forty-four".