81749206 has 32 divisors (see below), whose sum is σ = 157024512. Its totient is φ = 30987360.

The previous prime is 81749197. The next prime is 81749249. The reversal of 81749206 is 60294718.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1476 + ... + 12871.

It is an arithmetic number, because the mean of its divisors is an integer number (4907016).

Almost surely, 2^81749206 is an apocalyptic number.

81749206 is a deficient number, since it is larger than the sum of its proper divisors (75275306).

81749206 is a wasteful number, since it uses less digits than its factorization.

81749206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14404.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 81749206 is about 9041.5267516056. The cubic root of 81749206 is about 434.0047816727.

The spelling of 81749206 in words is "eighty-one million, seven hundred forty-nine thousand, two hundred six".