81213963 has 8 divisors (see below), whose sum is σ = 109297728. Its totient is φ = 53636424.

The previous prime is 81213959. The next prime is 81213973. The reversal of 81213963 is 36931218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81213963 - 2² = 81213959 is a prime.

It is a super-3 number, since 3×81213963³ (a number of 25 digits) contains 333 as substring.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126181 + ... + 126822.

It is an arithmetic number, because the mean of its divisors is an integer number (13662216).

Almost surely, 2^81213963 is an apocalyptic number.

81213963 is a deficient number, since it is larger than the sum of its proper divisors (28083765).

81213963 is a wasteful number, since it uses less digits than its factorization.

81213963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253113.

The product of its digits is 7776, while the sum is 33.

The square root of 81213963 is about 9011.8789938614. The cubic root of 81213963 is about 433.0555090295.

The spelling of 81213963 in words is "eighty-one million, two hundred thirteen thousand, nine hundred sixty-three".