12151821 has 16 divisors (see below), whose sum is σ = 18715968. Its totient is φ = 6931200.

The previous prime is 12151801. The next prime is 12151823. The reversal of 12151821 is 12815121.

12151821 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12151821 - 2¹⁹ = 11627533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12151823) 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, 10270 + ... + 11391.

It is an arithmetic number, because the mean of its divisors is an integer number (1169748).

Almost surely, 2^12151821 is an apocalyptic number.

12151821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12151821 is a deficient number, since it is larger than the sum of its proper divisors (6564147).

12151821 is a wasteful number, since it uses less digits than its factorization.

12151821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21692.

The product of its digits is 160, while the sum is 21.

The square root of 12151821 is about 3485.9462130102. The cubic root of 12151821 is about 229.9043143252.

Adding to 12151821 its reverse (12815121), we get a palindrome (24966942).

The spelling of 12151821 in words is "twelve million, one hundred fifty-one thousand, eight hundred twenty-one".