21503750081 has 8 divisors (see below), whose sum is σ = 23542122528. Its totient is φ = 19479292000.

The previous prime is 21503750057. The next prime is 21503750123. The reversal of 21503750081 is 18005730512.

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

It is a cyclic number.

It is not a de Polignac number, because 21503750081 - 2³⁰ = 20430008257 is a prime.

It is a super-2 number, since 2×21503750081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21503750581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3475355 + ... + 3481536.

It is an arithmetic number, because the mean of its divisors is an integer number (2942765316).

Almost surely, 2^21503750081 is an apocalyptic number.

It is an amenable number.

21503750081 is a deficient number, since it is larger than the sum of its proper divisors (2038372447).

21503750081 is a wasteful number, since it uses less digits than its factorization.

21503750081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6957183.

The product of its (nonzero) digits is 8400, while the sum is 32.

The spelling of 21503750081 in words is "twenty-one billion, five hundred three million, seven hundred fifty thousand, eighty-one".