1554317561 has 2 divisors, whose sum is σ = 1554317562. Its totient is φ = 1554317560.

The previous prime is 1554317543. The next prime is 1554317573. The reversal of 1554317561 is 1657134551.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1381237225 + 173080336 = 37165^2 + 13156^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1554317561 is a prime.

It is not a weakly prime, because it can be changed into another prime (1554317461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 777158780 + 777158781.

It is an arithmetic number, because the mean of its divisors is an integer number (777158781).

Almost surely, 2^1554317561 is an apocalyptic number.

It is an amenable number.

1554317561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1554317561 is an equidigital number, since it uses as much as digits as its factorization.

1554317561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63000, while the sum is 38.

The square root of 1554317561 is about 39424.8343179778. The cubic root of 1554317561 is about 1158.3680879979.

The spelling of 1554317561 in words is "one billion, five hundred fifty-four million, three hundred seventeen thousand, five hundred sixty-one".