81605470 has 8 divisors (see below), whose sum is σ = 146889864. Its totient is φ = 32642184.

The previous prime is 81605453. The next prime is 81605497. The reversal of 81605470 is 7450618.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4080264 + ... + 4080283.

It is an arithmetic number, because the mean of its divisors is an integer number (18361233).

Almost surely, 2^81605470 is an apocalyptic number.

81605470 is a deficient number, since it is larger than the sum of its proper divisors (65284394).

81605470 is a wasteful number, since it uses less digits than its factorization.

81605470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8160554.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 81605470 is about 9033.5745970241. The cubic root of 81605470 is about 433.7502686675.

The spelling of 81605470 in words is "eighty-one million, six hundred five thousand, four hundred seventy".