21531715473 has 8 divisors (see below), whose sum is σ = 28728344736. Its totient is φ = 14344781600.

The previous prime is 21531715453. The next prime is 21531715481. The reversal of 21531715473 is 37451713512.

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 21531715473 - 2⁶ = 21531715409 is a prime.

It is a super-2 number, since 2×21531715473² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21531715453) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2418663 + ... + 2427548.

It is an arithmetic number, because the mean of its divisors is an integer number (3591043092).

Almost surely, 2^21531715473 is an apocalyptic number.

It is an amenable number.

21531715473 is a deficient number, since it is larger than the sum of its proper divisors (7196629263).

21531715473 is a wasteful number, since it uses less digits than its factorization.

21531715473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4847695.

The product of its digits is 88200, while the sum is 39.

The spelling of 21531715473 in words is "twenty-one billion, five hundred thirty-one million, seven hundred fifteen thousand, four hundred seventy-three".