81449955 has 48 divisors (see below), whose sum is σ = 149909760. Its totient is φ = 42402528.

The previous prime is 81449939. The next prime is 81449971. The reversal of 81449955 is 55994418.

It is an interprime number because it is at equal distance from previous prime (81449939) and next prime (81449971).

It is not a de Polignac number, because 81449955 - 2⁴ = 81449939 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81449955.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51466 + ... + 53024.

It is an arithmetic number, because the mean of its divisors is an integer number (3123120).

Almost surely, 2^81449955 is an apocalyptic number.

81449955 is a deficient number, since it is larger than the sum of its proper divisors (68459805).

81449955 is a wasteful number, since it uses less digits than its factorization.

81449955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1622 (or 1610 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The square root of 81449955 is about 9024.9628808101. The cubic root of 81449955 is about 433.4745617908.

The spelling of 81449955 in words is "eighty-one million, four hundred forty-nine thousand, nine hundred fifty-five".