320661540 has 36 divisors (see below), whose sum is σ = 972673884. Its totient is φ = 85509696.

The previous prime is 320661503. The next prime is 320661547. The reversal of 320661540 is 45166023.

320661540 is a `hidden beast` number, since 3 + 2 + 0 + 6 + 615 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 67469796 + 253191744 = 8214^2 + 15912^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (320661547) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 890547 + ... + 890906.

It is an arithmetic number, because the mean of its divisors is an integer number (27018719).

Almost surely, 2^320661540 is an apocalyptic number.

320661540 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

320661540 is an abundant number, since it is smaller than the sum of its proper divisors (652012344).

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

320661540 is a wasteful number, since it uses less digits than its factorization.

320661540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781468 (or 1781463 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 320661540 is about 17907.0248785218. The cubic root of 320661540 is about 684.4613948603.

It can be divided in two parts, 320661 and 540, that added together give a triangular number (321201 = T₈₀₁).

The spelling of 320661540 in words is "three hundred twenty million, six hundred sixty-one thousand, five hundred forty".