991378622 has 8 divisors (see below), whose sum is σ = 1601457816. Its totient is φ = 457559352.

The previous prime is 991378607. The next prime is 991378627. The reversal of 991378622 is 226873199.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991378627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19064948 + ... + 19064999.

It is an arithmetic number, because the mean of its divisors is an integer number (200182227).

Almost surely, 2^991378622 is an apocalyptic number.

991378622 is a deficient number, since it is larger than the sum of its proper divisors (610079194).

991378622 is a wasteful number, since it uses less digits than its factorization.

991378622 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38129962.

The product of its digits is 326592, while the sum is 47.

The square root of 991378622 is about 31486.1655652129. The cubic root of 991378622 is about 997.1179088640.

The spelling of 991378622 in words is "nine hundred ninety-one million, three hundred seventy-eight thousand, six hundred twenty-two".