664647642 has 48 divisors (see below), whose sum is σ = 1460938752. Its totient is φ = 218363040.

The previous prime is 664647637. The next prime is 664647647. The reversal of 664647642 is 246746466.

It is an interprime number because it is at equal distance from previous prime (664647637) and next prime (664647647).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (664647647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 380892 + ... + 382632.

It is an arithmetic number, because the mean of its divisors is an integer number (30436224).

Almost surely, 2^664647642 is an apocalyptic number.

664647642 is an abundant number, since it is smaller than the sum of its proper divisors (796291110).

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

664647642 is a wasteful number, since it uses less digits than its factorization.

664647642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2043 (or 2040 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 45.

The square root of 664647642 is about 25780.7610826368. The cubic root of 664647642 is about 872.6976827030.

The spelling of 664647642 in words is "six hundred sixty-four million, six hundred forty-seven thousand, six hundred forty-two".