871401821 has 4 divisors (see below), whose sum is σ = 873369312. Its totient is φ = 869434332.

The previous prime is 871401787. The next prime is 871401833. The reversal of 871401821 is 128104178.

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: 128104178 = 2 ⋅64052089.

It is a cyclic number.

It is not a de Polignac number, because 871401821 - 2⁶ = 871401757 is a prime.

It is a super-2 number, since 2×871401821² = 1518682267284232082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (871401121) 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, 983081 + ... + 983966.

It is an arithmetic number, because the mean of its divisors is an integer number (218342328).

Almost surely, 2^871401821 is an apocalyptic number.

It is an amenable number.

871401821 is a deficient number, since it is larger than the sum of its proper divisors (1967491).

871401821 is a wasteful number, since it uses less digits than its factorization.

871401821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1967490.

The product of its (nonzero) digits is 3584, while the sum is 32.

The square root of 871401821 is about 29519.5159343781. The cubic root of 871401821 is about 955.1527294269.

Adding to 871401821 its reverse (128104178), we get a palindrome (999505999).

The spelling of 871401821 in words is "eight hundred seventy-one million, four hundred one thousand, eight hundred twenty-one".