749821 has 4 divisors (see below), whose sum is σ = 752544. Its totient is φ = 747100.

The previous prime is 749809. The next prime is 749843. The reversal of 749821 is 128947.

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 a de Polignac number, because none of the positive numbers 2^k-749821 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 (749851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 895 + ... + 1516.

It is an arithmetic number, because the mean of its divisors is an integer number (188136).

2⁷⁴⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

749821 is a deficient number, since it is larger than the sum of its proper divisors (2723).

749821 is a wasteful number, since it uses less digits than its factorization.

749821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722.

The product of its digits is 4032, while the sum is 31.

The square root of 749821 is about 865.9220519192. The cubic root of 749821 is about 90.8488009646.

The spelling of 749821 in words is "seven hundred forty-nine thousand, eight hundred twenty-one".