81770015506261 has 16 divisors (see below), whose sum is σ = 89067561659136. Its totient is φ = 74772767612416.

The previous prime is 81770015506199. The next prime is 81770015506279. The reversal of 81770015506261 is 16260551007718.

It is a happy number.

It is not a de Polignac number, because 81770015506261 - 2¹³ = 81770015498069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81770015516261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 373395811 + ... + 373614736.

It is an arithmetic number, because the mean of its divisors is an integer number (5566722603696).

Almost surely, 2^{81770015506261} is an apocalyptic number.

It is an amenable number.

81770015506261 is a deficient number, since it is larger than the sum of its proper divisors (7297546152875).

81770015506261 is a wasteful number, since it uses less digits than its factorization.

81770015506261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747010748.

The product of its (nonzero) digits is 705600, while the sum is 49.

The spelling of 81770015506261 in words is "eighty-one trillion, seven hundred seventy billion, fifteen million, five hundred six thousand, two hundred sixty-one".