21275217638 has 8 divisors (see below), whose sum is σ = 31913445960. Its totient is φ = 10637402320.

The previous prime is 21275217617. The next prime is 21275217703. The reversal of 21275217638 is 83671257212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142898 + ... + 250938.

It is an arithmetic number, because the mean of its divisors is an integer number (3989180745).

Almost surely, 2^21275217638 is an apocalyptic number.

21275217638 is a deficient number, since it is larger than the sum of its proper divisors (10638228322).

21275217638 is a wasteful number, since it uses less digits than its factorization.

21275217638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206502.

The product of its digits is 282240, while the sum is 44.

The spelling of 21275217638 in words is "twenty-one billion, two hundred seventy-five million, two hundred seventeen thousand, six hundred thirty-eight".