81005403958 has 4 divisors (see below), whose sum is σ = 121508105940. Its totient is φ = 40502701978.

The previous prime is 81005403953. The next prime is 81005404069. The reversal of 81005403958 is 85930450018.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81005403953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20251350988 + ... + 20251350991.

It is an arithmetic number, because the mean of its divisors is an integer number (30377026485).

Almost surely, 2^81005403958 is an apocalyptic number.

81005403958 is a deficient number, since it is larger than the sum of its proper divisors (40502701982).

81005403958 is a wasteful number, since it uses less digits than its factorization.

81005403958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40502701981.

The product of its (nonzero) digits is 172800, while the sum is 43.

The spelling of 81005403958 in words is "eighty-one billion, five million, four hundred three thousand, nine hundred fifty-eight".