1989042644 has 12 divisors (see below), whose sum is σ = 3486470484. Its totient is φ = 992908224.

The previous prime is 1989042637. The next prime is 1989042659. The reversal of 1989042644 is 4462409891.

It can be written as a sum of positive squares in 2 ways, for example, as 804856900 + 1184185744 = 28370^2 + 34412^2 .

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, 400499 + ... + 405434.

It is an arithmetic number, because the mean of its divisors is an integer number (290539207).

Almost surely, 2^1989042644 is an apocalyptic number.

It is an amenable number.

1989042644 is a deficient number, since it is larger than the sum of its proper divisors (1497427840).

1989042644 is a wasteful number, since it uses less digits than its factorization.

1989042644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806554 (or 806552 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 47.

The square root of 1989042644 is about 44598.6843303701. The cubic root of 1989042644 is about 1257.6159345147.

The spelling of 1989042644 in words is "one billion, nine hundred eighty-nine million, forty-two thousand, six hundred forty-four".