81202861 has 4 divisors (see below), whose sum is σ = 82414912. Its totient is φ = 79990812.

The previous prime is 81202853. The next prime is 81202873. The reversal of 81202861 is 16820218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16820218 = 2 ⋅8410109.

It is a cyclic number.

It is not a de Polignac number, because 81202861 - 2³ = 81202853 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 (81202841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605925 + ... + 606058.

It is an arithmetic number, because the mean of its divisors is an integer number (20603728).

Almost surely, 2^81202861 is an apocalyptic number.

It is an amenable number.

81202861 is a deficient number, since it is larger than the sum of its proper divisors (1212051).

81202861 is a wasteful number, since it uses less digits than its factorization.

81202861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212050.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81202861 is about 9011.2630080361. The cubic root of 81202861 is about 433.0357751431.

The spelling of 81202861 in words is "eighty-one million, two hundred two thousand, eight hundred sixty-one".