81377247629 has 2 divisors, whose sum is σ = 81377247630. Its totient is φ = 81377247628.

The previous prime is 81377247617. The next prime is 81377247667. The reversal of 81377247629 is 92674277318.

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., 78342890404 + 3034357225 = 279898^2 + 55085^2 .

It is a cyclic number.

It is not a de Polignac number, because 81377247629 - 2⁸ = 81377247373 is a prime.

It is a super-2 number, since 2×81377247629² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81377247689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688623814 + 40688623815.

It is an arithmetic number, because the mean of its divisors is an integer number (40688623815).

Almost surely, 2^81377247629 is an apocalyptic number.

It is an amenable number.

81377247629 is a deficient number, since it is larger than the sum of its proper divisors (1).

81377247629 is an equidigital number, since it uses as much as digits as its factorization.

81377247629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 56.

The spelling of 81377247629 in words is "eighty-one billion, three hundred seventy-seven million, two hundred forty-seven thousand, six hundred twenty-nine".