81374436 has 144 divisors (see below), whose sum is σ = 250252800. Its totient is φ = 22714560.

The previous prime is 81374407. The next prime is 81374441. The reversal of 81374436 is 63447318.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81374436.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 169645 + ... + 170123.

Almost surely, 2^81374436 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 81374436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125126400).

81374436 is an abundant number, since it is smaller than the sum of its proper divisors (168878364).

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

81374436 is a wasteful number, since it uses less digits than its factorization.

81374436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527 (or 508 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 81374436 is about 9020.7780152268. The cubic root of 81374436 is about 433.3405503072.

It can be divided in two parts, 81374 and 436, that added together give a triangular number (81810 = T₄₀₄).

The spelling of 81374436 in words is "eighty-one million, three hundred seventy-four thousand, four hundred thirty-six".