81379272 has 128 divisors (see below), whose sum is σ = 236476800. Its totient is φ = 23113728.

The previous prime is 81379241. The next prime is 81379283. The reversal of 81379272 is 27297318.

It is a super-2 number, since 2×81379272² = 13245171822499968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 81379272.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 355254 + ... + 355482.

It is an arithmetic number, because the mean of its divisors is an integer number (1847475).

Almost surely, 2^81379272 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 81379272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118238400).

81379272 is an abundant number, since it is smaller than the sum of its proper divisors (155097528).

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

81379272 is a wasteful number, since it uses less digits than its factorization.

81379272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 331 counting only the distinct ones).

The product of its digits is 42336, while the sum is 39.

The square root of 81379272 is about 9021.0460590776. The cubic root of 81379272 is about 433.3491344666.

The spelling of 81379272 in words is "eighty-one million, three hundred seventy-nine thousand, two hundred seventy-two".