20644534 has 4 divisors (see below), whose sum is σ = 30966804. Its totient is φ = 10322266.

The previous prime is 20644489. The next prime is 20644537. The reversal of 20644534 is 43544602.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20644537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5161132 + ... + 5161135.

It is an arithmetic number, because the mean of its divisors is an integer number (7741701).

Almost surely, 2^20644534 is an apocalyptic number.

20644534 is a deficient number, since it is larger than the sum of its proper divisors (10322270).

20644534 is a wasteful number, since it uses less digits than its factorization.

20644534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10322269.

The product of its (nonzero) digits is 11520, while the sum is 28.

The square root of 20644534 is about 4543.6256447907. The cubic root of 20644534 is about 274.3268782517.

The spelling of 20644534 in words is "twenty million, six hundred forty-four thousand, five hundred thirty-four".