81213952 has 20 divisors (see below), whose sum is σ = 162270306. Its totient is φ = 40606720.

The previous prime is 81213931. The next prime is 81213953. The reversal of 81213952 is 25931218.

It can be written as a sum of positive squares in only one way, i.e., 79995136 + 1218816 = 8944^2 + 1104^2 .

It is not an unprimeable number, because it can be changed into a prime (81213953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78799 + ... + 79822.

Almost surely, 2^81213952 is an apocalyptic number.

It is an amenable number.

81213952 is a deficient number, since it is larger than the sum of its proper divisors (81056354).

81213952 is an equidigital number, since it uses as much as digits as its factorization.

81213952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158639 (or 158623 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 81213952 is about 9011.8783835558. The cubic root of 81213952 is about 433.0554894778.

The spelling of 81213952 in words is "eighty-one million, two hundred thirteen thousand, nine hundred fifty-two".