15545921 has 2 divisors, whose sum is σ = 15545922. Its totient is φ = 15545920.

The previous prime is 15545891. The next prime is 15545927. The reversal of 15545921 is 12954551.

15545921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15295921 + 250000 = 3911^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 15545921 - 2¹⁴ = 15529537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (15545927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7772960 + 7772961.

It is an arithmetic number, because the mean of its divisors is an integer number (7772961).

Almost surely, 2^15545921 is an apocalyptic number.

It is an amenable number.

15545921 is a deficient number, since it is larger than the sum of its proper divisors (1).

15545921 is an equidigital number, since it uses as much as digits as its factorization.

15545921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9000, while the sum is 32.

The square root of 15545921 is about 3942.8315967081. The cubic root of 15545921 is about 249.5775318180.

The spelling of 15545921 in words is "fifteen million, five hundred forty-five thousand, nine hundred twenty-one".