1221616858 has 16 divisors (see below), whose sum is σ = 2284582464. Its totient is φ = 475954560.

The previous prime is 1221616849. The next prime is 1221616867. The reversal of 1221616858 is 8586161221.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1221616849) and next prime (1221616867).

It is a self number, because there is not a number n which added to its sum of digits gives 1221616858.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3966135 + ... + 3966442.

It is an arithmetic number, because the mean of its divisors is an integer number (142786404).

Almost surely, 2^1221616858 is an apocalyptic number.

1221616858 is a deficient number, since it is larger than the sum of its proper divisors (1062965606).

1221616858 is a wasteful number, since it uses less digits than its factorization.

1221616858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7932597.

The product of its digits is 46080, while the sum is 40.

The square root of 1221616858 is about 34951.6359846002. The cubic root of 1221616858 is about 1069.0015602540.

The spelling of 1221616858 in words is "one billion, two hundred twenty-one million, six hundred sixteen thousand, eight hundred fifty-eight".