7421991 has 4 divisors (see below), whose sum is σ = 9895992. Its totient is φ = 4947992.

The previous prime is 7421987. The next prime is 7421993. The reversal of 7421991 is 1991247.

7421991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 7421991 - 2² = 7421987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7421993) 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, 1236996 + ... + 1237001.

It is an arithmetic number, because the mean of its divisors is an integer number (2473998).

Almost surely, 2^7421991 is an apocalyptic number.

7421991 is a deficient number, since it is larger than the sum of its proper divisors (2474001).

7421991 is a wasteful number, since it uses less digits than its factorization.

7421991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2474000.

The product of its digits is 4536, while the sum is 33.

The square root of 7421991 is about 2724.3331294098. Note that the first 3 decimals coincide. The cubic root of 7421991 is about 195.0623600686.

The spelling of 7421991 in words is "seven million, four hundred twenty-one thousand, nine hundred ninety-one".