20097640 has 16 divisors (see below), whose sum is σ = 45219780. Its totient is φ = 8039040.

The previous prime is 20097629. The next prime is 20097643. The reversal of 20097640 is 4679002.

It can be written as a sum of positive squares in 2 ways, for example, as 18198756 + 1898884 = 4266^2 + 1378^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20097599 and 20097608.

It is not an unprimeable number, because it can be changed into a prime (20097643) 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 3 ways as a sum of consecutive naturals, for example, 251181 + ... + 251260.

Almost surely, 2^20097640 is an apocalyptic number.

20097640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20097640 is an abundant number, since it is smaller than the sum of its proper divisors (25122140).

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

20097640 is a wasteful number, since it uses less digits than its factorization.

20097640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502452 (or 502448 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 20097640 is about 4483.0391477211. The cubic root of 20097640 is about 271.8827709938.

The spelling of 20097640 in words is "twenty million, ninety-seven thousand, six hundred forty".