21425321633 has 16 divisors (see below), whose sum is σ = 22857414720. Its totient is φ = 20025501696.

The previous prime is 21425321591. The next prime is 21425321647. The reversal of 21425321633 is 33612352412.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21425321633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21425321633.

It is not an unprimeable number, because it can be changed into a prime (21425321653) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 399041 + ... + 449537.

It is an arithmetic number, because the mean of its divisors is an integer number (1428588420).

Almost surely, 2^21425321633 is an apocalyptic number.

It is an amenable number.

21425321633 is a deficient number, since it is larger than the sum of its proper divisors (1432093087).

21425321633 is a wasteful number, since it uses less digits than its factorization.

21425321633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50816.

The product of its digits is 25920, while the sum is 32.

The spelling of 21425321633 in words is "twenty-one billion, four hundred twenty-five million, three hundred twenty-one thousand, six hundred thirty-three".