671299640 has 128 divisors (see below), whose sum is σ = 1765152000. Its totient is φ = 227174400.

The previous prime is 671299633. The next prime is 671299649. The reversal of 671299640 is 46992176.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 671299591 and 671299600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671299649) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 492560 + ... + 493920.

It is an arithmetic number, because the mean of its divisors is an integer number (13790250).

Almost surely, 2^671299640 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 671299640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (882576000).

671299640 is an abundant number, since it is smaller than the sum of its proper divisors (1093852360).

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

671299640 is a wasteful number, since it uses less digits than its factorization.

671299640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461 (or 1457 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 44.

The square root of 671299640 is about 25909.4507853795. The cubic root of 671299640 is about 875.5994325208.

The spelling of 671299640 in words is "six hundred seventy-one million, two hundred ninety-nine thousand, six hundred forty".