42640991 has 8 divisors (see below), whose sum is σ = 44945280. Its totient is φ = 40392352.

The previous prime is 42640957. The next prime is 42641009. The reversal of 42640991 is 19904624.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42640991 is a prime.

It is a super-2 number, since 2×42640991² = 3636508226924162, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42640901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12335 + ... + 15408.

It is an arithmetic number, because the mean of its divisors is an integer number (5618160).

Almost surely, 2^42640991 is an apocalyptic number.

42640991 is a deficient number, since it is larger than the sum of its proper divisors (2304289).

42640991 is a wasteful number, since it uses less digits than its factorization.

42640991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27825.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 42640991 is about 6530.0069678370. The cubic root of 42640991 is about 349.3620788272.

The spelling of 42640991 in words is "forty-two million, six hundred forty thousand, nine hundred ninety-one".