1220820399 has 12 divisors (see below), whose sum is σ = 1769642056. Its totient is φ = 811002672.

The previous prime is 1220820373. The next prime is 1220820409. The reversal of 1220820399 is 9930280221.

It is not a de Polignac number, because 1220820399 - 2¹¹ = 1220818351 is a prime.

It is a super-2 number, since 2×1220820399² = 2980804893229038402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220820499) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 237112 + ... + 242205.

Almost surely, 2^1220820399 is an apocalyptic number.

1220820399 is a deficient number, since it is larger than the sum of its proper divisors (548821657).

1220820399 is a wasteful number, since it uses less digits than its factorization.

1220820399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479606 (or 479603 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 1220820399 is about 34940.2403969978. The cubic root of 1220820399 is about 1068.7691903397.

The spelling of 1220820399 in words is "one billion, two hundred twenty million, eight hundred twenty thousand, three hundred ninety-nine".