665407776 has 96 divisors (see below), whose sum is σ = 1918728000. Its totient is φ = 200238080.

The previous prime is 665407747. The next prime is 665407783. The reversal of 665407776 is 677704566.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×665407776² = 885535016722532352, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155230 + ... + 159458.

It is an arithmetic number, because the mean of its divisors is an integer number (19986750).

Almost surely, 2^665407776 is an apocalyptic number.

665407776 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665407776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (959364000).

665407776 is an abundant number, since it is smaller than the sum of its proper divisors (1253320224).

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

665407776 is a wasteful number, since it uses less digits than its factorization.

665407776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4402 (or 4394 counting only the distinct ones).

The product of its (nonzero) digits is 1481760, while the sum is 48.

The square root of 665407776 is about 25795.4991422922. The cubic root of 665407776 is about 873.0302471121.

The spelling of 665407776 in words is "six hundred sixty-five million, four hundred seven thousand, seven hundred seventy-six".