81220152 has 64 divisors (see below), whose sum is σ = 231547680. Its totient is φ = 23519232.

The previous prime is 81220141. The next prime is 81220159. The reversal of 81220152 is 25102218.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81220159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2353 + ... + 12960.

Almost surely, 2^81220152 is an apocalyptic number.

It is an amenable number.

81220152 is an abundant number, since it is smaller than the sum of its proper divisors (150327528).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81220152 is a wasteful number, since it uses less digits than its factorization.

81220152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15352 (or 15348 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 81220152 is about 9012.2223674297. Note that the first 3 decimals coincide. The cubic root of 81220152 is about 433.0665092416.

The spelling of 81220152 in words is "eighty-one million, two hundred twenty thousand, one hundred fifty-two".