81606621547 has 8 divisors (see below), whose sum is σ = 89036470512. Its totient is φ = 74178616800.

The previous prime is 81606621541. The next prime is 81606621589. The reversal of 81606621547 is 74512660618.

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

It is a cyclic number.

It is not a de Polignac number, because 81606621547 - 2³⁵ = 47246883179 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81606621497 and 81606621506.

It is not an unprimeable number, because it can be changed into a prime (81606621541) 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, 367704 + ... + 546277.

It is an arithmetic number, because the mean of its divisors is an integer number (11129558814).

Almost surely, 2^81606621547 is an apocalyptic number.

81606621547 is a deficient number, since it is larger than the sum of its proper divisors (7429848965).

81606621547 is a wasteful number, since it uses less digits than its factorization.

81606621547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922109.

The product of its (nonzero) digits is 483840, while the sum is 46.

The spelling of 81606621547 in words is "eighty-one billion, six hundred six million, six hundred twenty-one thousand, five hundred forty-seven".