1220020999 has 4 divisors (see below), whose sum is σ = 1221497064. Its totient is φ = 1218544936.

The previous prime is 1220020987. The next prime is 1220021009. The reversal of 1220020999 is 9990200221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9990200221 = 37061 ⋅269561.

It is a cyclic number.

It is not a de Polignac number, because 1220020999 - 2²³ = 1211632391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220020909) 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, 736792 + ... + 738445.

It is an arithmetic number, because the mean of its divisors is an integer number (305374266).

Almost surely, 2^1220020999 is an apocalyptic number.

1220020999 is a deficient number, since it is larger than the sum of its proper divisors (1476065).

1220020999 is an equidigital number, since it uses as much as digits as its factorization.

1220020999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1476064.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 1220020999 is about 34928.7989916630. The cubic root of 1220020999 is about 1068.5358607300.

The spelling of 1220020999 in words is "one billion, two hundred twenty million, twenty thousand, nine hundred ninety-nine".