19745890 has 16 divisors (see below), whose sum is σ = 35771832. Its totient is φ = 7847424.

The previous prime is 19745879. The next prime is 19745893. The reversal of 19745890 is 9854791.

It can be written as a sum of positive squares in 4 ways, for example, as 17783089 + 1962801 = 4217^2 + 1401^2 .

It is not an unprimeable number, because it can be changed into a prime (19745893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4719 + ... + 7858.

Almost surely, 2^19745890 is an apocalyptic number.

19745890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19745890 is a deficient number, since it is larger than the sum of its proper divisors (16025942).

19745890 is a wasteful number, since it uses less digits than its factorization.

19745890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12741.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 19745890 is about 4443.6347734709. The cubic root of 19745890 is about 270.2872571458.

The spelling of 19745890 in words is "nineteen million, seven hundred forty-five thousand, eight hundred ninety".