21528935938 has 4 divisors (see below), whose sum is σ = 32293403910. Its totient is φ = 10764467968.

The previous prime is 21528935917. The next prime is 21528935969. The reversal of 21528935938 is 83953982512.

It is a happy number.

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., 13625192529 + 7903743409 = 116727^2 + 88903^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5382233983 + ... + 5382233986.

Almost surely, 2^21528935938 is an apocalyptic number.

21528935938 is a deficient number, since it is larger than the sum of its proper divisors (10764467972).

21528935938 is a wasteful number, since it uses less digits than its factorization.

21528935938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10764467971.

The product of its digits is 4665600, while the sum is 55.

The spelling of 21528935938 in words is "twenty-one billion, five hundred twenty-eight million, nine hundred thirty-five thousand, nine hundred thirty-eight".