81121105401 has 16 divisors (see below), whose sum is σ = 124442736000. Its totient is φ = 46043808768.

The previous prime is 81121105391. The next prime is 81121105411. The reversal of 81121105401 is 10450112118.

It is an interprime number because it is at equal distance from previous prime (81121105391) and next prime (81121105411).

It is not a de Polignac number, because 81121105401 - 2⁵ = 81121105369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81121105411) 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, 12959656 + ... + 12965913.

It is an arithmetic number, because the mean of its divisors is an integer number (7777671000).

Almost surely, 2^81121105401 is an apocalyptic number.

It is an amenable number.

81121105401 is a deficient number, since it is larger than the sum of its proper divisors (43321630599).

81121105401 is a wasteful number, since it uses less digits than its factorization.

81121105401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25925728.

The product of its (nonzero) digits is 320, while the sum is 24.

Adding to 81121105401 its reverse (10450112118), we get a palindrome (91571217519).

The spelling of 81121105401 in words is "eighty-one billion, one hundred twenty-one million, one hundred five thousand, four hundred one".