20091690 has 24 divisors (see below), whose sum is σ = 52238628. Its totient is φ = 5357760.

The previous prime is 20091679. The next prime is 20091691. The reversal of 20091690 is 9619002.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19105641 + 986049 = 4371^2 + 993^2 .

It is a super-2 number, since 2×20091690² = 807352014112200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20091691) 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 11 ways as a sum of consecutive naturals, for example, 111531 + ... + 111710.

Almost surely, 2^20091690 is an apocalyptic number.

20091690 is an abundant number, since it is smaller than the sum of its proper divisors (32146938).

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

20091690 is a wasteful number, since it uses less digits than its factorization.

20091690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223254 (or 223251 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 20091690 is about 4482.3754862796. The cubic root of 20091690 is about 271.8559376250.

The spelling of 20091690 in words is "twenty million, ninety-one thousand, six hundred ninety".