291042640 has 80 divisors (see below), whose sum is σ = 784985472. Its totient is φ = 98284032.

The previous prime is 291042611. The next prime is 291042643. The reversal of 291042640 is 46240192.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 291042599 and 291042608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291042643) 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 15 ways as a sum of consecutive naturals, for example, 33642 + ... + 41398.

Almost surely, 2^291042640 is an apocalyptic number.

291042640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 291042640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (392492736).

291042640 is an abundant number, since it is smaller than the sum of its proper divisors (493942832).

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

291042640 is a wasteful number, since it uses less digits than its factorization.

291042640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7844 (or 7838 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 291042640 is about 17059.9718639862. The cubic root of 291042640 is about 662.7029040303.

The spelling of 291042640 in words is "two hundred ninety-one million, forty-two thousand, six hundred forty".