15504016421 has 2 divisors, whose sum is σ = 15504016422. Its totient is φ = 15504016420.

The previous prime is 15504016361. The next prime is 15504016441. The reversal of 15504016421 is 12461040551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10606116196 + 4897900225 = 102986^2 + 69985^2 .

It is an emirp because it is prime and its reverse (12461040551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15504016421 - 2¹⁴ = 15504000037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15504016441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7752008210 + 7752008211.

It is an arithmetic number, because the mean of its divisors is an integer number (7752008211).

Almost surely, 2^15504016421 is an apocalyptic number.

It is an amenable number.

15504016421 is a deficient number, since it is larger than the sum of its proper divisors (1).

15504016421 is an equidigital number, since it uses as much as digits as its factorization.

15504016421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4800, while the sum is 29.

Adding to 15504016421 its reverse (12461040551), we get a palindrome (27965056972).

The spelling of 15504016421 in words is "fifteen billion, five hundred four million, sixteen thousand, four hundred twenty-one".