1221001993 has 8 divisors (see below), whose sum is σ = 1272196800. Its totient is φ = 1170413328.

The previous prime is 1221001987. The next prime is 1221002009. The reversal of 1221001993 is 3991001221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221001993 - 2²⁵ = 1187447561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221001933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147421 + ... + 155482.

It is an arithmetic number, because the mean of its divisors is an integer number (159024600).

Almost surely, 2^1221001993 is an apocalyptic number.

It is an amenable number.

1221001993 is a deficient number, since it is larger than the sum of its proper divisors (51194807).

1221001993 is a wasteful number, since it uses less digits than its factorization.

1221001993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303071.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 1221001993 is about 34942.8389373273. The cubic root of 1221001993 is about 1068.8221799660.

The spelling of 1221001993 in words is "one billion, two hundred twenty-one million, one thousand, nine hundred ninety-three".