991619201 has 4 divisors (see below), whose sum is σ = 992116272. Its totient is φ = 991122132.

The previous prime is 991619149. The next prime is 991619249. The reversal of 991619201 is 102916199.

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-991619201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991619261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245531 + ... + 249536.

It is an arithmetic number, because the mean of its divisors is an integer number (248029068).

Almost surely, 2^991619201 is an apocalyptic number.

It is an amenable number.

991619201 is a deficient number, since it is larger than the sum of its proper divisors (497071).

991619201 is a wasteful number, since it uses less digits than its factorization.

991619201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497070.

The product of its (nonzero) digits is 8748, while the sum is 38.

The square root of 991619201 is about 31489.9857256239. The cubic root of 991619201 is about 997.1985595936.

The spelling of 991619201 in words is "nine hundred ninety-one million, six hundred nineteen thousand, two hundred one".