15554423981 has 2 divisors, whose sum is σ = 15554423982. Its totient is φ = 15554423980.

The previous prime is 15554423971. The next prime is 15554424037. The reversal of 15554423981 is 18932445551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14697925225 + 856498756 = 121235^2 + 29266^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15554423981 is a prime.

It is a super-2 number, since 2×15554423981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15554423971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7777211990 + 7777211991.

It is an arithmetic number, because the mean of its divisors is an integer number (7777211991).

Almost surely, 2^15554423981 is an apocalyptic number.

It is an amenable number.

15554423981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15554423981 is an equidigital number, since it uses as much as digits as its factorization.

15554423981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864000, while the sum is 47.

The spelling of 15554423981 in words is "fifteen billion, five hundred fifty-four million, four hundred twenty-three thousand, nine hundred eighty-one".