81779288 has 8 divisors (see below), whose sum is σ = 153336180. Its totient is φ = 40889640.

The previous prime is 81779281. The next prime is 81779293. The reversal of 81779288 is 88297718.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81779281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5111198 + ... + 5111213.

Almost surely, 2^81779288 is an apocalyptic number.

It is an amenable number.

81779288 is a deficient number, since it is larger than the sum of its proper divisors (71556892).

81779288 is a wasteful number, since it uses less digits than its factorization.

81779288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10222417 (or 10222413 counting only the distinct ones).

The product of its digits is 451584, while the sum is 50.

The square root of 81779288 is about 9043.1901450760. The cubic root of 81779288 is about 434.0580100419.

The spelling of 81779288 in words is "eighty-one million, seven hundred seventy-nine thousand, two hundred eighty-eight".