81212601 has 16 divisors (see below), whose sum is σ = 109678464. Its totient is φ = 53449344.

The previous prime is 81212597. The next prime is 81212603. The reversal of 81212601 is 10621218.

It is not a de Polignac number, because 81212601 - 2² = 81212597 is a prime.

It is a super-2 number, since 2×81212601² = 13190973122370402, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81212603) 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, 86205 + ... + 87141.

It is an arithmetic number, because the mean of its divisors is an integer number (6854904).

Almost surely, 2^81212601 is an apocalyptic number.

It is an amenable number.

81212601 is a deficient number, since it is larger than the sum of its proper divisors (28465863).

81212601 is a wasteful number, since it uses less digits than its factorization.

81212601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1280.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 81212601 is about 9011.8034266178. The cubic root of 81212601 is about 433.0530881613.

Adding to 81212601 its reverse (10621218), we get a palindrome (91833819).

The spelling of 81212601 in words is "eighty-one million, two hundred twelve thousand, six hundred one".