21406215633 has 48 divisors (see below), whose sum is σ = 32219486208. Its totient is φ = 12627014400.

The previous prime is 21406215631. The next prime is 21406215637. The reversal of 21406215633 is 33651260412.

It is not a de Polignac number, because 21406215633 - 2¹ = 21406215631 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21406215594 and 21406215603.

It is not an unprimeable number, because it can be changed into a prime (21406215631) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2438973 + ... + 2447733.

It is an arithmetic number, because the mean of its divisors is an integer number (671239296).

Almost surely, 2^21406215633 is an apocalyptic number.

It is an amenable number.

21406215633 is a deficient number, since it is larger than the sum of its proper divisors (10813270575).

21406215633 is a wasteful number, since it uses less digits than its factorization.

21406215633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8966 (or 8955 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The spelling of 21406215633 in words is "twenty-one billion, four hundred six million, two hundred fifteen thousand, six hundred thirty-three".