81557049 has 8 divisors (see below), whose sum is σ = 124277440. Its totient is φ = 46604016.

The previous prime is 81557027. The next prime is 81557071. The reversal of 81557049 is 94075518.

It is an interprime number because it is at equal distance from previous prime (81557027) and next prime (81557071).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81557049 - 2⁹ = 81556537 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81556998 and 81557016.

It is not an unprimeable number, because it can be changed into a prime (81557009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1941814 + ... + 1941855.

It is an arithmetic number, because the mean of its divisors is an integer number (15534680).

Almost surely, 2^81557049 is an apocalyptic number.

It is an amenable number.

81557049 is a deficient number, since it is larger than the sum of its proper divisors (42720391).

81557049 is a wasteful number, since it uses less digits than its factorization.

81557049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3883679.

The product of its (nonzero) digits is 50400, while the sum is 39.

The square root of 81557049 is about 9030.8941417780. The cubic root of 81557049 is about 433.6644624213.

The spelling of 81557049 in words is "eighty-one million, five hundred fifty-seven thousand, forty-nine".