1985800690 has 8 divisors (see below), whose sum is σ = 3574441260. Its totient is φ = 794320272.

The previous prime is 1985800631. The next prime is 1985800711. The reversal of 1985800690 is 960085891.

It can be written as a sum of positive squares in 2 ways, for example, as 1974824721 + 10975969 = 44439^2 + 3313^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×1985800690² = 7886808760808952200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1985800690.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99290025 + ... + 99290044.

Almost surely, 2^1985800690 is an apocalyptic number.

1985800690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1985800690 is a deficient number, since it is larger than the sum of its proper divisors (1588640570).

1985800690 is a wasteful number, since it uses less digits than its factorization.

1985800690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198580076.

The product of its (nonzero) digits is 155520, while the sum is 46.

The square root of 1985800690 is about 44562.3236602402. The cubic root of 1985800690 is about 1256.9322973982.

The spelling of 1985800690 in words is "one billion, nine hundred eighty-five million, eight hundred thousand, six hundred ninety".