821440749 has 16 divisors (see below), whose sum is σ = 1112614272. Its totient is φ = 538979328.

The previous prime is 821440729. The next prime is 821440751. The reversal of 821440749 is 947044128.

It is not a de Polignac number, because 821440749 - 2¹² = 821436653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821440709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106429 + ... + 113885.

It is an arithmetic number, because the mean of its divisors is an integer number (69538392).

Almost surely, 2^821440749 is an apocalyptic number.

It is an amenable number.

821440749 is a deficient number, since it is larger than the sum of its proper divisors (291173523).

821440749 is a wasteful number, since it uses less digits than its factorization.

821440749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8036.

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 821440749 is about 28660.7876549128. The cubic root of 821440749 is about 936.5380232362.

The spelling of 821440749 in words is "eight hundred twenty-one million, four hundred forty thousand, seven hundred forty-nine".