81642411 has 24 divisors (see below), whose sum is σ = 128739520. Its totient is φ = 51560712.

The previous prime is 81642409. The next prime is 81642413. The reversal of 81642411 is 11424618.

It is a happy number.

81642411 is a `hidden beast` number, since 8 + 1 + 642 + 4 + 11 = 666.

It is an interprime number because it is at equal distance from previous prime (81642409) and next prime (81642413).

It is not a de Polignac number, because 81642411 - 2¹ = 81642409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81642413) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4225 + ... + 13458.

Almost surely, 2^81642411 is an apocalyptic number.

81642411 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81642411 is a deficient number, since it is larger than the sum of its proper divisors (47097109).

81642411 is a wasteful number, since it uses less digits than its factorization.

81642411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17717 (or 17705 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 81642411 is about 9035.6190158727. The cubic root of 81642411 is about 433.8157085271.

The spelling of 81642411 in words is "eighty-one million, six hundred forty-two thousand, four hundred eleven".