85778821 has 8 divisors (see below), whose sum is σ = 90949824. Its totient is φ = 80621760.

The previous prime is 85778813. The next prime is 85778831. The reversal of 85778821 is 12887758.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 85778821 - 2³ = 85778813 is a prime.

It is a super-2 number, since 2×85778821² = 14716012264300082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85778831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10926 + ... + 17056.

It is an arithmetic number, because the mean of its divisors is an integer number (11368728).

Almost surely, 2^85778821 is an apocalyptic number.

It is an amenable number.

85778821 is a deficient number, since it is larger than the sum of its proper divisors (5171003).

85778821 is a wasteful number, since it uses less digits than its factorization.

85778821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6971.

The product of its digits is 250880, while the sum is 46.

The square root of 85778821 is about 9261.6856457127. The cubic root of 85778821 is about 441.0217662620.

The spelling of 85778821 in words is "eighty-five million, seven hundred seventy-eight thousand, eight hundred twenty-one".