20397634 has 4 divisors (see below), whose sum is σ = 30596454. Its totient is φ = 10198816.

The previous prime is 20397631. The next prime is 20397647. The reversal of 20397634 is 43679302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 43679302 = 2 ⋅21839651.

It can be written as a sum of positive squares in only one way, i.e., 14861025 + 5536609 = 3855^2 + 2353^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20397634.

It is not an unprimeable number, because it can be changed into a prime (20397631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5099407 + ... + 5099410.

Almost surely, 2^20397634 is an apocalyptic number.

20397634 is a deficient number, since it is larger than the sum of its proper divisors (10198820).

20397634 is a wasteful number, since it uses less digits than its factorization.

20397634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10198819.

The product of its (nonzero) digits is 27216, while the sum is 34.

The square root of 20397634 is about 4516.3739880572. The cubic root of 20397634 is about 273.2288777285.

The spelling of 20397634 in words is "twenty million, three hundred ninety-seven thousand, six hundred thirty-four".