664767221760 has 156 divisors (see below), whose sum is σ = 2304245693412. Its totient is φ = 177271209984.

The previous prime is 664767221743. The next prime is 664767221777. The reversal of 664767221760 is 67122767466.

It is an interprime number because it is at equal distance from previous prime (664767221743) and next prime (664767221777).

It can be written as a sum of positive squares in 2 ways, for example, as 178746310656 + 486020911104 = 422784^2 + 697152^2 .

It is a junction number, because it is equal to n+sod(n) for n = 664767221697 and 664767221706.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1618977 + ... + 1987616.

It is an arithmetic number, because the mean of its divisors is an integer number (14770805727).

Almost surely, 2^664767221760 is an apocalyptic number.

664767221760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

664767221760 is an abundant number, since it is smaller than the sum of its proper divisors (1639478471652).

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

664767221760 is a wasteful number, since it uses less digits than its factorization.

664767221760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3606628 (or 3606603 counting only the distinct ones).

The product of its (nonzero) digits is 7112448, while the sum is 54.

The spelling of 664767221760 in words is "six hundred sixty-four billion, seven hundred sixty-seven million, two hundred twenty-one thousand, seven hundred sixty".