81602381 has 4 divisors (see below), whose sum is σ = 93259872. Its totient is φ = 69944892.

The previous prime is 81602333. The next prime is 81602399. The reversal of 81602381 is 18320618.

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.

It is a cyclic number.

It is not a de Polignac number, because 81602381 - 2¹⁴ = 81585997 is a prime.

It is a super-3 number, since 3×81602381³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81602581) 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, 5828735 + ... + 5828748.

It is an arithmetic number, because the mean of its divisors is an integer number (23314968).

Almost surely, 2^81602381 is an apocalyptic number.

It is an amenable number.

81602381 is a deficient number, since it is larger than the sum of its proper divisors (11657491).

81602381 is a wasteful number, since it uses less digits than its factorization.

81602381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11657490.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 81602381 is about 9033.4036221128. The cubic root of 81602381 is about 433.7447957031.

Adding to 81602381 its reverse (18320618), we get a palindrome (99922999).

The spelling of 81602381 in words is "eighty-one million, six hundred two thousand, three hundred eighty-one".