1989644139 has 24 divisors (see below), whose sum is σ = 3390446592. Its totient is φ = 1100262960.

The previous prime is 1989644089. The next prime is 1989644143. The reversal of 1989644139 is 9314469891.

It is a happy number.

1989644139 is a `hidden beast` number, since 198 + 9 + 6 + 441 + 3 + 9 = 666.

It is not a de Polignac number, because 1989644139 - 2⁹ = 1989643627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1989644939) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 507429 + ... + 511334.

It is an arithmetic number, because the mean of its divisors is an integer number (141268608).

Almost surely, 2^1989644139 is an apocalyptic number.

1989644139 is a deficient number, since it is larger than the sum of its proper divisors (1400802453).

1989644139 is a wasteful number, since it uses less digits than its factorization.

1989644139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1018807 (or 1018804 counting only the distinct ones).

The product of its digits is 1679616, while the sum is 54.

The square root of 1989644139 is about 44605.4272370527. The cubic root of 1989644139 is about 1257.7426912169.

The spelling of 1989644139 in words is "one billion, nine hundred eighty-nine million, six hundred forty-four thousand, one hundred thirty-nine".