81772405 has 48 divisors (see below), whose sum is σ = 119719152. Its totient is φ = 53222400.

The previous prime is 81772393. The next prime is 81772463. The reversal of 81772405 is 50427718.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 213444 + 81558961 = 462^2 + 9031^2 .

It is not a de Polignac number, because 81772405 - 2⁷ = 81772277 is a prime.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

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, 290865 + ... + 291145.

It is an arithmetic number, because the mean of its divisors is an integer number (2494149).

Almost surely, 2^81772405 is an apocalyptic number.

It is an amenable number.

81772405 is a deficient number, since it is larger than the sum of its proper divisors (37946747).

81772405 is a wasteful number, since it uses less digits than its factorization.

81772405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 81772405 is about 9042.8095744630. The cubic root of 81772405 is about 434.0458321210.

The spelling of 81772405 in words is "eighty-one million, seven hundred seventy-two thousand, four hundred five".