19999690 has 8 divisors (see below), whose sum is σ = 35999460. Its totient is φ = 7999872.

The previous prime is 19999663. The next prime is 19999697. The reversal of 19999690 is 9699991.

It can be written as a sum of positive squares in 2 ways, for example, as 17247409 + 2752281 = 4153^2 + 1659^2 .

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

It is a super-2 number, since 2×19999690² = 799975200192200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19999697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 999975 + ... + 999994.

Almost surely, 2^19999690 is an apocalyptic number.

19999690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19999690 is a deficient number, since it is larger than the sum of its proper divisors (15999770).

19999690 is a wasteful number, since it uses less digits than its factorization.

19999690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1999976.

The product of its (nonzero) digits is 354294, while the sum is 52.

The square root of 19999690 is about 4472.1012958116. The cubic root of 19999690 is about 271.4403592031.

The spelling of 19999690 in words is "nineteen million, nine hundred ninety-nine thousand, six hundred ninety".