20639426 has 4 divisors (see below), whose sum is σ = 30959142. Its totient is φ = 10319712.

The previous prime is 20639407. The next prime is 20639471. The reversal of 20639426 is 62493602.

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., 19351201 + 1288225 = 4399^2 + 1135^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20639392 and 20639401.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5159855 + ... + 5159858.

Almost surely, 2^20639426 is an apocalyptic number.

20639426 is a deficient number, since it is larger than the sum of its proper divisors (10319716).

20639426 is a wasteful number, since it uses less digits than its factorization.

20639426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10319715.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 20639426 is about 4543.0635038485. The cubic root of 20639426 is about 274.3042511602.

The spelling of 20639426 in words is "twenty million, six hundred thirty-nine thousand, four hundred twenty-six".