71981906 has 8 divisors (see below), whose sum is σ = 108243324. Its totient is φ = 35900800.

The previous prime is 71981879. The next prime is 71981933. The reversal of 71981906 is 60918917.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (71981879) and next prime (71981933).

It can be written as a sum of positive squares in 2 ways, for example, as 54834025 + 17147881 = 7405^2 + 4141^2 .

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

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, 44075 + ... + 45678.

Almost surely, 2^71981906 is an apocalyptic number.

71981906 is a deficient number, since it is larger than the sum of its proper divisors (36261418).

71981906 is a wasteful number, since it uses less digits than its factorization.

71981906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90156.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 71981906 is about 8484.2151080698. The cubic root of 71981906 is about 415.9819125827.

The spelling of 71981906 in words is "seventy-one million, nine hundred eighty-one thousand, nine hundred six".