1221405993 has 8 divisors (see below), whose sum is σ = 1809490400. Its totient is φ = 814270644.

The previous prime is 1221405979. The next prime is 1221406019. The reversal of 1221405993 is 3995041221.

1221405993 is a `hidden beast` number, since 1 + 2 + 21 + 40 + 599 + 3 = 666.

It is not a de Polignac number, because 1221405993 - 2⁸ = 1221405737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221405923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22618603 + ... + 22618656.

It is an arithmetic number, because the mean of its divisors is an integer number (226186300).

Almost surely, 2^1221405993 is an apocalyptic number.

It is an amenable number.

1221405993 is a deficient number, since it is larger than the sum of its proper divisors (588084407).

1221405993 is an equidigital number, since it uses as much as digits as its factorization.

1221405993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45237268 (or 45237262 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 1221405993 is about 34948.6193289520. The cubic root of 1221405993 is about 1068.9400494283.

The spelling of 1221405993 in words is "one billion, two hundred twenty-one million, four hundred five thousand, nine hundred ninety-three".