15555555401 has 2 divisors, whose sum is σ = 15555555402. Its totient is φ = 15555555400.

The previous prime is 15555555397. The next prime is 15555555409. The reversal of 15555555401 is 10455555551.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15500499001 + 55056400 = 124501^2 + 7420^2 .

It is a cyclic number.

It is not a de Polignac number, because 15555555401 - 2² = 15555555397 is a prime.

It is a super-3 number, since 3×15555555401³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (15555555409) 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, 7777777700 + 7777777701.

It is an arithmetic number, because the mean of its divisors is an integer number (7777777701).

Almost surely, 2^15555555401 is an apocalyptic number.

It is an amenable number.

15555555401 is a deficient number, since it is larger than the sum of its proper divisors (1).

15555555401 is an equidigital number, since it uses as much as digits as its factorization.

15555555401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 312500, while the sum is 41.

The spelling of 15555555401 in words is "fifteen billion, five hundred fifty-five million, five hundred fifty-five thousand, four hundred one".