20667512644 has 9 divisors (see below), whose sum is σ = 36168650301. Its totient is φ = 10333612560.

The previous prime is 20667512623. The next prime is 20667512653. The reversal of 20667512644 is 44621576602.

The square root of 20667512644 is 143762.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 69522244 + 20597990400 = 8338^2 + 143520^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20667512644.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 251584 + ... + 323464.

Almost surely, 2^20667512644 is an apocalyptic number.

20667512644 is the 143762-nd square number.

It is an amenable number.

20667512644 is a deficient number, since it is larger than the sum of its proper divisors (15501137657).

20667512644 is an frugal number, since it uses more digits than its factorization.

20667512644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143766 (or 71883 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 43.

The spelling of 20667512644 in words is "twenty billion, six hundred sixty-seven million, five hundred twelve thousand, six hundred forty-four".