1989751555 has 16 divisors (see below), whose sum is σ = 2606126688. Its totient is φ = 1446336000.

The previous prime is 1989751541. The next prime is 1989751559. The reversal of 1989751555 is 5551579891.

It is a de Polignac number, because none of the positive numbers 2^k-1989751555 is a prime.

It is a super-2 number, since 2×1989751555² = 7918222501249836050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a junction number, because it is equal to n+sod(n) for n = 1989751496 and 1989751505.

It is not an unprimeable number, because it can be changed into a prime (1989751559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110485 + ... + 127225.

It is an arithmetic number, because the mean of its divisors is an integer number (162882918).

Almost surely, 2^1989751555 is an apocalyptic number.

1989751555 is a deficient number, since it is larger than the sum of its proper divisors (616375133).

1989751555 is a wasteful number, since it uses less digits than its factorization.

1989751555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18918.

The product of its digits is 2835000, while the sum is 55.

The square root of 1989751555 is about 44606.6312895291. The cubic root of 1989751555 is about 1257.7653249557.

The spelling of 1989751555 in words is "one billion, nine hundred eighty-nine million, seven hundred fifty-one thousand, five hundred fifty-five".