80071821 has 10 divisors (see below), whose sum is σ = 119613582. Its totient is φ = 53381160.

The previous prime is 80071801. The next prime is 80071841. The reversal of 80071821 is 12817008.

It is an interprime number because it is at equal distance from previous prime (80071801) and next prime (80071841).

It can be written as a sum of positive squares in only one way, i.e., 48024900 + 32046921 = 6930^2 + 5661^2 .

It is not a de Polignac number, because 80071821 - 2²² = 75877517 is a prime.

It is a super-2 number, since 2×80071821² = 12822993036512082, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80071801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 494190 + ... + 494351.

Almost surely, 2^80071821 is an apocalyptic number.

80071821 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

80071821 is a deficient number, since it is larger than the sum of its proper divisors (39541761).

80071821 is an equidigital number, since it uses as much as digits as its factorization.

80071821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 988553 (or 988544 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 80071821 is about 8948.2859252485. The cubic root of 80071821 is about 431.0158441499.

Adding to 80071821 its reverse (12817008), we get a palindrome (92888829).

The spelling of 80071821 in words is "eighty million, seventy-one thousand, eight hundred twenty-one".