12121440 has 48 divisors (see below), whose sum is σ = 38184048. Its totient is φ = 3232256.

The previous prime is 12121427. The next prime is 12121451. The reversal of 12121440 is 4412121.

12121440 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 a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12147 + ... + 13106.

It is an arithmetic number, because the mean of its divisors is an integer number (795501).

Almost surely, 2^12121440 is an apocalyptic number.

12121440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12121440 is an abundant number, since it is smaller than the sum of its proper divisors (26062608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12121440 is a wasteful number, since it uses less digits than its factorization.

12121440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25271 (or 25263 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 12121440 is about 3481.5858455595. The cubic root of 12121440 is about 229.7125583749.

Adding to 12121440 its reverse (4412121), we get a palindrome (16533561).

It can be divided in two parts, 12121 and 440, that added together give a triangular number (12561 = T₁₅₈).

The spelling of 12121440 in words is "twelve million, one hundred twenty-one thousand, four hundred forty".