121553440 has 24 divisors (see below), whose sum is σ = 287170380. Its totient is φ = 48621312.

The previous prime is 121553423. The next prime is 121553447. The reversal of 121553440 is 44355121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 113465104 + 8088336 = 10652^2 + 2844^2 .

It is not an unprimeable number, because it can be changed into a prime (121553447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 379695 + ... + 380014.

Almost surely, 2^121553440 is an apocalyptic number.

121553440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121553440 is an abundant number, since it is smaller than the sum of its proper divisors (165616940).

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

121553440 is an equidigital number, since it uses as much as digits as its factorization.

121553440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759724 (or 759716 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 121553440 is about 11025.1276636600. The cubic root of 121553440 is about 495.3616919137.

The spelling of 121553440 in words is "one hundred twenty-one million, five hundred fifty-three thousand, four hundred forty".