1667394720 has 120 divisors (see below), whose sum is σ = 5884559604. Its totient is φ = 444635136.

The previous prime is 1667394661. The next prime is 1667394727. The reversal of 1667394720 is 274937661.

It can be written as a sum of positive squares in 2 ways, for example, as 1628606736 + 38787984 = 40356^2 + 6228^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1667394727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 51369 + ... + 77288.

Almost surely, 2^1667394720 is an apocalyptic number.

1667394720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1667394720 is an abundant number, since it is smaller than the sum of its proper divisors (4217164884).

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

1667394720 is a wasteful number, since it uses less digits than its factorization.

1667394720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128684 (or 128667 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The square root of 1667394720 is about 40833.7448686745. The cubic root of 1667394720 is about 1185.8037168996.

The spelling of 1667394720 in words is "one billion, six hundred sixty-seven million, three hundred ninety-four thousand, seven hundred twenty".