121640491 has 32 divisors (see below), whose sum is σ = 156902400. Its totient is φ = 93760128.

The previous prime is 121640437. The next prime is 121640509. The reversal of 121640491 is 194046121.

It is not a de Polignac number, because 121640491 - 2¹⁵ = 121607723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121640291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 133660 + ... + 134566.

It is an arithmetic number, because the mean of its divisors is an integer number (4903200).

Almost surely, 2^121640491 is an apocalyptic number.

121640491 is a deficient number, since it is larger than the sum of its proper divisors (35261909).

121640491 is an equidigital number, since it uses as much as digits as its factorization.

121640491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968 (or 954 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 121640491 is about 11029.0748025390. The cubic root of 121640491 is about 495.4799154725.

The spelling of 121640491 in words is "one hundred twenty-one million, six hundred forty thousand, four hundred ninety-one".