81772416 has 192 divisors, whose sum is σ = 267321600. Its totient is φ = 24675840.

The previous prime is 81772393. The next prime is 81772463. The reversal of 81772416 is 61427718.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 342025 + ... + 342263.

It is an arithmetic number, because the mean of its divisors is an integer number (1392300).

Almost surely, 2^81772416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81772416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133660800).

81772416 is an abundant number, since it is smaller than the sum of its proper divisors (185549184).

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

81772416 is a wasteful number, since it uses less digits than its factorization.

81772416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 255 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 81772416 is about 9042.8101826810. The cubic root of 81772416 is about 434.0458515836.

The spelling of 81772416 in words is "eighty-one million, seven hundred seventy-two thousand, four hundred sixteen".