81903915 has 12 divisors (see below), whose sum is σ = 141966864. Its totient is φ = 43682064.

The previous prime is 81903901. The next prime is 81903923. The reversal of 81903915 is 51930918.

It is a happy number.

It is not a de Polignac number, because 81903915 - 2¹¹ = 81901867 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81903915.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 909999 + ... + 910088.

It is an arithmetic number, because the mean of its divisors is an integer number (11830572).

Almost surely, 2^81903915 is an apocalyptic number.

81903915 is a deficient number, since it is larger than the sum of its proper divisors (60062949).

81903915 is a wasteful number, since it uses less digits than its factorization.

81903915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1820098 (or 1820095 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 81903915 is about 9050.0781764579. The cubic root of 81903915 is about 434.2783913991.

The spelling of 81903915 in words is "eighty-one million, nine hundred three thousand, nine hundred fifteen".