77221831 has 4 divisors (see below), whose sum is σ = 77785632. Its totient is φ = 76658032.

The previous prime is 77221811. The next prime is 77221841. The reversal of 77221831 is 13812277.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13812277 = 53 ⋅260609.

It is a cyclic number.

It is not a de Polignac number, because 77221831 - 2¹⁷ = 77090759 is a prime.

It is a super-2 number, since 2×77221831² = 11926422365985122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77221793 and 77221802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77221811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 281695 + ... + 281968.

It is an arithmetic number, because the mean of its divisors is an integer number (19446408).

Almost surely, 2^77221831 is an apocalyptic number.

77221831 is a deficient number, since it is larger than the sum of its proper divisors (563801).

77221831 is a wasteful number, since it uses less digits than its factorization.

77221831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563800.

The product of its digits is 4704, while the sum is 31.

The square root of 77221831 is about 8787.5952910907. The cubic root of 77221831 is about 425.8402403725.

The spelling of 77221831 in words is "seventy-seven million, two hundred twenty-one thousand, eight hundred thirty-one".