20640674 has 4 divisors (see below), whose sum is σ = 30961014. Its totient is φ = 10320336.

The previous prime is 20640667. The next prime is 20640679. The reversal of 20640674 is 47604602.

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., 14010049 + 6630625 = 3743^2 + 2575^2 .

It is not an unprimeable number, because it can be changed into a prime (20640679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5160167 + ... + 5160170.

Almost surely, 2^20640674 is an apocalyptic number.

20640674 is a deficient number, since it is larger than the sum of its proper divisors (10320340).

20640674 is a wasteful number, since it uses less digits than its factorization.

20640674 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10320339.

The product of its (nonzero) digits is 8064, while the sum is 29.

The square root of 20640674 is about 4543.2008540235. The cubic root of 20640674 is about 274.3097798153.

The spelling of 20640674 in words is "twenty million, six hundred forty thousand, six hundred seventy-four".