81418949 has 4 divisors (see below), whose sum is σ = 81464160. Its totient is φ = 81373740.

The previous prime is 81418943. The next prime is 81418951. The reversal of 81418949 is 94981418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81418949 - 2⁸ = 81418693 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81418943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19787 + ... + 23544.

It is an arithmetic number, because the mean of its divisors is an integer number (20366040).

Almost surely, 2^81418949 is an apocalyptic number.

It is an amenable number.

81418949 is a deficient number, since it is larger than the sum of its proper divisors (45211).

81418949 is a wasteful number, since it uses less digits than its factorization.

81418949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45210.

The product of its digits is 82944, while the sum is 44.

The square root of 81418949 is about 9023.2449263001. The cubic root of 81418949 is about 433.4195504320.

The spelling of 81418949 in words is "eighty-one million, four hundred eighteen thousand, nine hundred forty-nine".