21661465732432 has 20 divisors (see below), whose sum is σ = 42361324344576. Its totient is φ = 10729511062880.

The previous prime is 21661465732429. The next prime is 21661465732433. The reversal of 21661465732432 is 23423756416612.

It is a self number, because there is not a number n which added to its sum of digits gives 21661465732432.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661465732433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6326360944 + ... + 6326364367.

Almost surely, 2^{21661465732432} is an apocalyptic number.

It is an amenable number.

21661465732432 is a deficient number, since it is larger than the sum of its proper divisors (20699858612144).

21661465732432 is a wasteful number, since it uses less digits than its factorization.

21661465732432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12652725426 (or 12652725420 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 52.

The spelling of 21661465732432 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred sixty-five million, seven hundred thirty-two thousand, four hundred thirty-two".