81530371657406 has 16 divisors (see below), whose sum is σ = 139791676124160. Its totient is φ = 34935256675320.

The previous prime is 81530371657387. The next prime is 81530371657409. The reversal of 81530371657406 is 60475617303518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81530371657409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 527518130 + ... + 527672661.

It is an arithmetic number, because the mean of its divisors is an integer number (8736979757760).

Almost surely, 2^{81530371657406} is an apocalyptic number.

81530371657406 is a deficient number, since it is larger than the sum of its proper divisors (58261304466754).

81530371657406 is a wasteful number, since it uses less digits than its factorization.

81530371657406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055196319.

The product of its (nonzero) digits is 12700800, while the sum is 56.

The spelling of 81530371657406 in words is "eighty-one trillion, five hundred thirty billion, three hundred seventy-one million, six hundred fifty-seven thousand, four hundred six".