77700021 has 8 divisors (see below), whose sum is σ = 118400064. Its totient is φ = 44400000.

The previous prime is 77700001. The next prime is 77700023. The reversal of 77700021 is 12000777.

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

It is not a de Polignac number, because 77700021 - 2⁵ = 77699989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 77699964 and 77700000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77700023) 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, 1849980 + ... + 1850021.

It is an arithmetic number, because the mean of its divisors is an integer number (14800008).

Almost surely, 2^77700021 is an apocalyptic number.

It is an amenable number.

77700021 is a deficient number, since it is larger than the sum of its proper divisors (40700043).

77700021 is a wasteful number, since it uses less digits than its factorization.

77700021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3700011.

The product of its (nonzero) digits is 686, while the sum is 24.

The square root of 77700021 is about 8814.7615395994. The cubic root of 77700021 is about 426.7174260764.

Adding to 77700021 its reverse (12000777), we get a palindrome (89700798).

The spelling of 77700021 in words is "seventy-seven million, seven hundred thousand, twenty-one".