821428101 has 16 divisors (see below), whose sum is σ = 1310541120. Its totient is φ = 505494000.

The previous prime is 821428093. The next prime is 821428109. The reversal of 821428101 is 101824128.

It is an interprime number because it is at equal distance from previous prime (821428093) and next prime (821428109).

It is not a de Polignac number, because 821428101 - 2³ = 821428093 is a prime.

It is a super-2 number, since 2×821428101² = 1349488250224932402, 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 (821428109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1169775 + ... + 1170476.

It is an arithmetic number, because the mean of its divisors is an integer number (81908820).

Almost surely, 2^821428101 is an apocalyptic number.

It is an amenable number.

821428101 is a deficient number, since it is larger than the sum of its proper divisors (489113019).

821428101 is a wasteful number, since it uses less digits than its factorization.

821428101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340273 (or 2340267 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 27.

The square root of 821428101 is about 28660.5670041610. The cubic root of 821428101 is about 936.5332164810.

It can be divided in two parts, 8214 and 28101, that added together give a triangular number (36315 = T₂₆₉).

The spelling of 821428101 in words is "eight hundred twenty-one million, four hundred twenty-eight thousand, one hundred one".