7990001221 has 4 divisors (see below), whose sum is σ = 7990354944. Its totient is φ = 7989647500.

The previous prime is 7990001213. The next prime is 7990001231. The reversal of 7990001221 is 1221000997.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7990001221 - 2³ = 7990001213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7990001231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140485 + ... + 188986.

It is an arithmetic number, because the mean of its divisors is an integer number (1997588736).

Almost surely, 2^7990001221 is an apocalyptic number.

It is an amenable number.

7990001221 is a deficient number, since it is larger than the sum of its proper divisors (353723).

7990001221 is a wasteful number, since it uses less digits than its factorization.

7990001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353722.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 7990001221 is about 89386.8067502134. The cubic root of 7990001221 is about 1999.1664210380.

The spelling of 7990001221 in words is "seven billion, nine hundred ninety million, one thousand, two hundred twenty-one".