1220400491 has 2 divisors, whose sum is σ = 1220400492. Its totient is φ = 1220400490.

The previous prime is 1220400479. The next prime is 1220400499. The reversal of 1220400491 is 1940040221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1220400491 - 2¹⁴ = 1220384107 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1220400499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610200245 + 610200246.

It is an arithmetic number, because the mean of its divisors is an integer number (610200246).

Almost surely, 2^1220400491 is an apocalyptic number.

1220400491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220400491 is an equidigital number, since it uses as much as digits as its factorization.

1220400491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1220400491 is about 34934.2309347150. The cubic root of 1220400491 is about 1068.6466399091.

The spelling of 1220400491 in words is "one billion, two hundred twenty million, four hundred thousand, four hundred ninety-one".