81474391 has 2 divisors, whose sum is σ = 81474392. Its totient is φ = 81474390.

The previous prime is 81474373. The next prime is 81474461. The reversal of 81474391 is 19347418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81474391 - 2¹⁵ = 81441623 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81474391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81474301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40737195 + 40737196.

It is an arithmetic number, because the mean of its divisors is an integer number (40737196).

Almost surely, 2^81474391 is an apocalyptic number.

81474391 is a deficient number, since it is larger than the sum of its proper divisors (1).

81474391 is an equidigital number, since it uses as much as digits as its factorization.

81474391 is an evil number, because the sum of its binary digits is even.

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

The square root of 81474391 is about 9026.3165798680. The cubic root of 81474391 is about 433.5179067105.

The spelling of 81474391 in words is "eighty-one million, four hundred seventy-four thousand, three hundred ninety-one".