761821 has 8 divisors (see below), whose sum is σ = 827064. Its totient is φ = 698880.

The previous prime is 761809. The next prime is 761833. The reversal of 761821 is 128167.

It is an interprime number because it is at equal distance from previous prime (761809) and next prime (761833).

It can be written as a sum of positive squares in 4 ways, for example, as 236196 + 525625 = 486^2 + 725^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-761821 is a prime.

It is a Duffinian number.

761821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (761861) 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, 151 + ... + 1243.

It is an arithmetic number, because the mean of its divisors is an integer number (103383).

2⁷⁶¹⁸²¹ is an apocalyptic number.

It is an amenable number.

761821 is a deficient number, since it is larger than the sum of its proper divisors (65243).

761821 is a wasteful number, since it uses less digits than its factorization.

761821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1151.

The product of its digits is 672, while the sum is 25.

The square root of 761821 is about 872.8235789666. The cubic root of 761821 is about 91.3308809377.

Adding to 761821 its reverse (128167), we get a palindrome (889988).

The spelling of 761821 in words is "seven hundred sixty-one thousand, eight hundred twenty-one".