81219490560 has 360 divisors, whose sum is σ = 312978629040. Its totient is φ = 19992158208.

The previous prime is 81219490559. The next prime is 81219490567. The reversal of 81219490560 is 6509491218.

81219490560 is a `hidden beast` number, since 81 + 2 + 1 + 9 + 4 + 9 + 0 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-2 number, since 2×81219490560² (a number of 23 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (81219490567) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1317711 + ... + 1377969.

Almost surely, 2^81219490560 is an apocalyptic number.

81219490560 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81219490560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156489314520).

81219490560 is an abundant number, since it is smaller than the sum of its proper divisors (231759138480).

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

81219490560 is a wasteful number, since it uses less digits than its factorization.

81219490560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60305 (or 60282 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 81219490560 in words is "eighty-one billion, two hundred nineteen million, four hundred ninety thousand, five hundred sixty".