81994612149 has 64 divisors (see below), whose sum is σ = 125411328000. Its totient is φ = 52913911680.

The previous prime is 81994612099. The next prime is 81994612171. The reversal of 81994612149 is 94121649918.

81994612149 is a `hidden beast` number, since 8 + 1 + 9 + 9 + 4 + 612 + 14 + 9 = 666.

It is not a de Polignac number, because 81994612149 - 2⁹ = 81994611637 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81994612095 and 81994612104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81994612549) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 126730144 + ... + 126730790.

It is an arithmetic number, because the mean of its divisors is an integer number (1959552000).

Almost surely, 2^81994612149 is an apocalyptic number.

It is an amenable number.

81994612149 is a deficient number, since it is larger than the sum of its proper divisors (43416715851).

81994612149 is a wasteful number, since it uses less digits than its factorization.

81994612149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415 (or 1409 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The spelling of 81994612149 in words is "eighty-one billion, nine hundred ninety-four million, six hundred twelve thousand, one hundred forty-nine".