665421732456 has 256 divisors, whose sum is σ = 1939942932480. Its totient is φ = 188521344000.

The previous prime is 665421732413. The next prime is 665421732463. The reversal of 665421732456 is 654237124566.

It is a junction number, because it is equal to n+sod(n) for n = 665421732399 and 665421732408.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42481266 + ... + 42496926.

It is an arithmetic number, because the mean of its divisors is an integer number (7577902080).

Almost surely, 2^665421732456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665421732456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (969971466240).

665421732456 is an abundant number, since it is smaller than the sum of its proper divisors (1274521200024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665421732456 is a wasteful number, since it uses less digits than its factorization.

665421732456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15928 (or 15924 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 51.

The spelling of 665421732456 in words is "six hundred sixty-five billion, four hundred twenty-one million, seven hundred thirty-two thousand, four hundred fifty-six".