121564621 has 4 divisors (see below), whose sum is σ = 122452092. Its totient is φ = 120677152.

The previous prime is 121564589. The next prime is 121564627. The reversal of 121564621 is 126465121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126465121 = 19 ⋅6656059.

It can be written as a sum of positive squares in 2 ways, for example, as 87796900 + 33767721 = 9370^2 + 5811^2 .

It is a cyclic number.

It is not a de Polignac number, because 121564621 - 2⁵ = 121564589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121564621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121564627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 443530 + ... + 443803.

It is an arithmetic number, because the mean of its divisors is an integer number (30613023).

Almost surely, 2^121564621 is an apocalyptic number.

It is an amenable number.

121564621 is a deficient number, since it is larger than the sum of its proper divisors (887471).

121564621 is an equidigital number, since it uses as much as digits as its factorization.

121564621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887470.

The product of its digits is 2880, while the sum is 28.

The square root of 121564621 is about 11025.6347209582. The cubic root of 121564621 is about 495.3768799365.

The spelling of 121564621 in words is "one hundred twenty-one million, five hundred sixty-four thousand, six hundred twenty-one".