1551116681 has 2 divisors, whose sum is σ = 1551116682. Its totient is φ = 1551116680.

The previous prime is 1551116663. The next prime is 1551116687. The reversal of 1551116681 is 1866111551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 999571456 + 551545225 = 31616^2 + 23485^2 .

It is a cyclic number.

It is not a de Polignac number, because 1551116681 - 2¹⁴ = 1551100297 is a prime.

It is a super-2 number, since 2×1551116681² = 4811925916152911522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1551116687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 775558340 + 775558341.

It is an arithmetic number, because the mean of its divisors is an integer number (775558341).

Almost surely, 2^1551116681 is an apocalyptic number.

It is an amenable number.

1551116681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1551116681 is an equidigital number, since it uses as much as digits as its factorization.

1551116681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 35.

The square root of 1551116681 is about 39384.2186795676. The cubic root of 1551116681 is about 1157.5723807223.

The spelling of 1551116681 in words is "one billion, five hundred fifty-one million, one hundred sixteen thousand, six hundred eighty-one".