1221564406 has 16 divisors (see below), whose sum is σ = 1869018768. Its totient is φ = 598629600.

The previous prime is 1221564401. The next prime is 1221564457. The reversal of 1221564406 is 6044651221.

It is a happy number.

It is a super-2 number, since 2×1221564406² = 2984439196012265672, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221564401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16836 + ... + 52216.

It is an arithmetic number, because the mean of its divisors is an integer number (116813673).

Almost surely, 2^1221564406 is an apocalyptic number.

1221564406 is a deficient number, since it is larger than the sum of its proper divisors (647454362).

1221564406 is a wasteful number, since it uses less digits than its factorization.

1221564406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35727.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 1221564406 is about 34950.8856254030. The cubic root of 1221564406 is about 1068.9862602926.

The spelling of 1221564406 in words is "one billion, two hundred twenty-one million, five hundred sixty-four thousand, four hundred six".