1220021999 has 16 divisors (see below), whose sum is σ = 1422973440. Its totient is φ = 1024302240.

The previous prime is 1220021989. The next prime is 1220022029. The reversal of 1220021999 is 9991200221.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220021999 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220021969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 253982 + ... + 258740.

It is an arithmetic number, because the mean of its divisors is an integer number (88935840).

Almost surely, 2^1220021999 is an apocalyptic number.

1220021999 is a deficient number, since it is larger than the sum of its proper divisors (202951441).

1220021999 is an equidigital number, since it uses as much as digits as its factorization.

1220021999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5510.

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 1220021999 is about 34928.8133064953. The cubic root of 1220021999 is about 1068.5361526746.

The spelling of 1220021999 in words is "one billion, two hundred twenty million, twenty-one thousand, nine hundred ninety-nine".