991242501 has 4 divisors (see below), whose sum is σ = 1321656672. Its totient is φ = 660828332.

The previous prime is 991242491. The next prime is 991242503. The reversal of 991242501 is 105242199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991242501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991242503) 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 3 ways as a sum of consecutive naturals, for example, 165207081 + ... + 165207086.

It is an arithmetic number, because the mean of its divisors is an integer number (330414168).

Almost surely, 2^991242501 is an apocalyptic number.

It is an amenable number.

991242501 is a deficient number, since it is larger than the sum of its proper divisors (330414171).

991242501 is a wasteful number, since it uses less digits than its factorization.

991242501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330414170.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 991242501 is about 31484.0038908650. The cubic root of 991242501 is about 997.0722704313.

The spelling of 991242501 in words is "nine hundred ninety-one million, two hundred forty-two thousand, five hundred one".