20397658 has 4 divisors (see below), whose sum is σ = 30596490. Its totient is φ = 10198828.

The previous prime is 20397647. The next prime is 20397673. The reversal of 20397658 is 85679302.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19035769 + 1361889 = 4363^2 + 1167^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 20397658.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5099413 + ... + 5099416.

Almost surely, 2^20397658 is an apocalyptic number.

20397658 is a deficient number, since it is larger than the sum of its proper divisors (10198832).

20397658 is a wasteful number, since it uses less digits than its factorization.

20397658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10198831.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 20397658 is about 4516.3766450552. The cubic root of 20397658 is about 273.2289848895.

The spelling of 20397658 in words is "twenty million, three hundred ninety-seven thousand, six hundred fifty-eight".