21537447537 has 8 divisors (see below), whose sum is σ = 28732929280. Its totient is φ = 14350132080.

The previous prime is 21537447517. The next prime is 21537447541. The reversal of 21537447537 is 73574473512.

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

It is not a de Polignac number, because 21537447537 - 2⁷ = 21537447409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21537447517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2035414 + ... + 2045967.

It is an arithmetic number, because the mean of its divisors is an integer number (3591616160).

Almost surely, 2^21537447537 is an apocalyptic number.

It is an amenable number.

21537447537 is a deficient number, since it is larger than the sum of its proper divisors (7195481743).

21537447537 is a wasteful number, since it uses less digits than its factorization.

21537447537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4083143.

The product of its digits is 2469600, while the sum is 48.

The spelling of 21537447537 in words is "twenty-one billion, five hundred thirty-seven million, four hundred forty-seven thousand, five hundred thirty-seven".