787921 has 4 divisors (see below), whose sum is σ = 790000. Its totient is φ = 785844.

The previous prime is 787907. The next prime is 787939. The reversal of 787921 is 129787.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 129787 = 7 ⋅18541.

It is a cyclic number.

It is not a de Polignac number, because 787921 - 2⁷ = 787793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (787981) 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, 291 + ... + 1288.

It is an arithmetic number, because the mean of its divisors is an integer number (197500).

2⁷⁸⁷⁹²¹ is an apocalyptic number.

It is an amenable number.

787921 is a deficient number, since it is larger than the sum of its proper divisors (2079).

787921 is a wasteful number, since it uses less digits than its factorization.

787921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2078.

The product of its digits is 7056, while the sum is 34.

The square root of 787921 is about 887.6491423981. The cubic root of 787921 is about 92.3621906989.

The spelling of 787921 in words is "seven hundred eighty-seven thousand, nine hundred twenty-one".