81648137 has 16 divisors (see below), whose sum is σ = 88784640. Its totient is φ = 74851392.

The previous prime is 81648131. The next prime is 81648139. The reversal of 81648137 is 73184618.

It is a cyclic number.

It is not a de Polignac number, because 81648137 - 2⁴ = 81648121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81648137.

It is not an unprimeable number, because it can be changed into a prime (81648131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111023 + ... + 111755.

It is an arithmetic number, because the mean of its divisors is an integer number (5549040).

Almost surely, 2^81648137 is an apocalyptic number.

It is an amenable number.

81648137 is a deficient number, since it is larger than the sum of its proper divisors (7136503).

81648137 is a wasteful number, since it uses less digits than its factorization.

81648137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 952.

The product of its digits is 32256, while the sum is 38.

The square root of 81648137 is about 9035.9358674130. The cubic root of 81648137 is about 433.8258501951.

The spelling of 81648137 in words is "eighty-one million, six hundred forty-eight thousand, one hundred thirty-seven".