1220661999 has 24 divisors (see below), whose sum is σ = 1880358480. Its totient is φ = 760382208.

The previous prime is 1220661947. The next prime is 1220662019. The reversal of 1220661999 is 9991660221.

1220661999 is a `hidden beast` number, since 1 + 2 + 20 + 6 + 619 + 9 + 9 = 666.

It is not a de Polignac number, because 1220661999 - 2¹³ = 1220653807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220661929) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7432 + ... + 49965.

It is an arithmetic number, because the mean of its divisors is an integer number (78348270).

Almost surely, 2^1220661999 is an apocalyptic number.

1220661999 is a deficient number, since it is larger than the sum of its proper divisors (659696481).

1220661999 is a wasteful number, since it uses less digits than its factorization.

1220661999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57559 (or 57556 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 1220661999 is about 34937.9735960745. The cubic root of 1220661999 is about 1068.7229644951.

The spelling of 1220661999 in words is "one billion, two hundred twenty million, six hundred sixty-one thousand, nine hundred ninety-nine".