81554568 has 16 divisors (see below), whose sum is σ = 203886480. Its totient is φ = 27184848.

The previous prime is 81554567. The next prime is 81554569. The reversal of 81554568 is 86545518.

It is an interprime number because it is at equal distance from previous prime (81554567) and next prime (81554569).

It is a super-2 number, since 2×81554568² = 13302295123333248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81554567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1699030 + ... + 1699077.

It is an arithmetic number, because the mean of its divisors is an integer number (12742905).

Almost surely, 2^81554568 is an apocalyptic number.

It is an amenable number.

81554568 is an abundant number, since it is smaller than the sum of its proper divisors (122331912).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81554568 is a wasteful number, since it uses less digits than its factorization.

81554568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3398116 (or 3398112 counting only the distinct ones).

The product of its digits is 192000, while the sum is 42.

The square root of 81554568 is about 9030.7567789195. The cubic root of 81554568 is about 433.6600649578.

The spelling of 81554568 in words is "eighty-one million, five hundred fifty-four thousand, five hundred sixty-eight".