19931227681 has 2 divisors, whose sum is σ = 19931227682. Its totient is φ = 19931227680.

The previous prime is 19931227663. The next prime is 19931227831. The reversal of 19931227681 is 18672213991.

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., 17853235456 + 2077992225 = 133616^2 + 45585^2 .

It is a cyclic number.

It is not a de Polignac number, because 19931227681 - 2¹³ = 19931219489 is a prime.

It is a super-2 number, since 2×19931227681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19931227661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9965613840 + 9965613841.

It is an arithmetic number, because the mean of its divisors is an integer number (9965613841).

Almost surely, 2^19931227681 is an apocalyptic number.

It is an amenable number.

19931227681 is a deficient number, since it is larger than the sum of its proper divisors (1).

19931227681 is an equidigital number, since it uses as much as digits as its factorization.

19931227681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 326592, while the sum is 49.

The spelling of 19931227681 in words is "nineteen billion, nine hundred thirty-one million, two hundred twenty-seven thousand, six hundred eighty-one".