1989611640 has 64 divisors (see below), whose sum is σ = 6632042400. Its totient is φ = 530562816.

The previous prime is 1989611599. The next prime is 1989611653. The reversal of 1989611640 is 461169891.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 920037 + ... + 922196.

Almost surely, 2^1989611640 is an apocalyptic number.

1989611640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1989611640 is an abundant number, since it is smaller than the sum of its proper divisors (4642430760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1989611640 is a wasteful number, since it uses less digits than its factorization.

1989611640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1842253 (or 1842243 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 1989611640 is about 44605.0629413299. The cubic root of 1989611640 is about 1257.7358431577.

The spelling of 1989611640 in words is "one billion, nine hundred eighty-nine million, six hundred eleven thousand, six hundred forty".