21650344642 has 4 divisors (see below), whose sum is σ = 32475516966. Its totient is φ = 10825172320.

The previous prime is 21650344633. The next prime is 21650344649. The reversal of 21650344642 is 24644305612.

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., 19190283841 + 2460060801 = 138529^2 + 49599^2 .

It is not an unprimeable number, because it can be changed into a prime (21650344649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5412586159 + ... + 5412586162.

Almost surely, 2^21650344642 is an apocalyptic number.

21650344642 is a deficient number, since it is larger than the sum of its proper divisors (10825172324).

21650344642 is a wasteful number, since it uses less digits than its factorization.

21650344642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10825172323.

The product of its (nonzero) digits is 138240, while the sum is 37.

The spelling of 21650344642 in words is "twenty-one billion, six hundred fifty million, three hundred forty-four thousand, six hundred forty-two".