12457821 has 16 divisors (see below), whose sum is σ = 17725824. Its totient is φ = 7755264.

The previous prime is 12457817. The next prime is 12457859. The reversal of 12457821 is 12875421.

It is not a de Polignac number, because 12457821 - 2² = 12457817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12457871) 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, 6096 + ... + 7878.

It is an arithmetic number, because the mean of its divisors is an integer number (1107864).

Almost surely, 2^12457821 is an apocalyptic number.

It is an amenable number.

12457821 is a deficient number, since it is larger than the sum of its proper divisors (5268003).

12457821 is a wasteful number, since it uses less digits than its factorization.

12457821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940.

The product of its digits is 4480, while the sum is 30.

The square root of 12457821 is about 3529.5638540760. The cubic root of 12457821 is about 231.8181107546.

The spelling of 12457821 in words is "twelve million, four hundred fifty-seven thousand, eight hundred twenty-one".