761865821 has 4 divisors (see below), whose sum is σ = 762166332. Its totient is φ = 761565312.

The previous prime is 761865803. The next prime is 761865847. The reversal of 761865821 is 128568167.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 349166596 + 412699225 = 18686^2 + 20315^2 .

It is a cyclic number.

It is not a de Polignac number, because 761865821 - 2¹⁰ = 761864797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (761865121) 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, 146420 + ... + 151533.

It is an arithmetic number, because the mean of its divisors is an integer number (190541583).

Almost surely, 2^761865821 is an apocalyptic number.

It is an amenable number.

761865821 is a deficient number, since it is larger than the sum of its proper divisors (300511).

761865821 is a wasteful number, since it uses less digits than its factorization.

761865821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300510.

The product of its digits is 161280, while the sum is 44.

The square root of 761865821 is about 27601.9169805287. The cubic root of 761865821 is about 913.3267202385.

The spelling of 761865821 in words is "seven hundred sixty-one million, eight hundred sixty-five thousand, eight hundred twenty-one".