81925836505501 has 2 divisors, whose sum is σ = 81925836505502. Its totient is φ = 81925836505500.

The previous prime is 81925836505477. The next prime is 81925836505547. The reversal of 81925836505501 is 10550563852918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46429573905625 + 35496262599876 = 6813925^2 + 5957874^2 .

It is a cyclic number.

It is not a de Polignac number, because 81925836505501 - 2²³ = 81925828116893 is a prime.

It is a super-2 number, since 2×81925836505501² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81925836505561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40962918252750 + 40962918252751.

It is an arithmetic number, because the mean of its divisors is an integer number (40962918252751).

Almost surely, 2^{81925836505501} is an apocalyptic number.

It is an amenable number.

81925836505501 is a deficient number, since it is larger than the sum of its proper divisors (1).

81925836505501 is an equidigital number, since it uses as much as digits as its factorization.

81925836505501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960000, while the sum is 58.

The spelling of 81925836505501 in words is "eighty-one trillion, nine hundred twenty-five billion, eight hundred thirty-six million, five hundred five thousand, five hundred one".