4721991 has 4 divisors (see below), whose sum is σ = 6295992. Its totient is φ = 3147992.

The previous prime is 4721963. The next prime is 4721999. The reversal of 4721991 is 1991274.

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 4721991 - 2¹¹ = 4719943 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4721999) 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, 786996 + ... + 787001.

It is an arithmetic number, because the mean of its divisors is an integer number (1573998).

Almost surely, 2^4721991 is an apocalyptic number.

4721991 is a deficient number, since it is larger than the sum of its proper divisors (1574001).

4721991 is a wasteful number, since it uses less digits than its factorization.

4721991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1574000.

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

The square root of 4721991 is about 2173.0142659449. The cubic root of 4721991 is about 167.7677132717.

The spelling of 4721991 in words is "four million, seven hundred twenty-one thousand, nine hundred ninety-one".