15201661421 has 2 divisors, whose sum is σ = 15201661422. Its totient is φ = 15201661420.

The previous prime is 15201661403. The next prime is 15201661441. The reversal of 15201661421 is 12416610251.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12532802500 + 2668858921 = 111950^2 + 51661^2 .

It is a cyclic number.

It is not a de Polignac number, because 15201661421 - 2⁶ = 15201661357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15201661441) 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 as a sum of consecutive naturals, namely, 7600830710 + 7600830711.

It is an arithmetic number, because the mean of its divisors is an integer number (7600830711).

Almost surely, 2^15201661421 is an apocalyptic number.

It is an amenable number.

15201661421 is a deficient number, since it is larger than the sum of its proper divisors (1).

15201661421 is an equidigital number, since it uses as much as digits as its factorization.

15201661421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The spelling of 15201661421 in words is "fifteen billion, two hundred one million, six hundred sixty-one thousand, four hundred twenty-one".