123271821 has 8 divisors (see below), whose sum is σ = 182624960. Its totient is φ = 82181196.

The previous prime is 123271817. The next prime is 123271843. The reversal of 123271821 is 128172321.

It is not a de Polignac number, because 123271821 - 2² = 123271817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 4565623 = 123271821 / (1 + 2 + 3 + 2 + 7 + 1 + 8 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123271801) 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, 2282785 + ... + 2282838.

It is an arithmetic number, because the mean of its divisors is an integer number (22828120).

Almost surely, 2^123271821 is an apocalyptic number.

It is an amenable number.

123271821 is a deficient number, since it is larger than the sum of its proper divisors (59353139).

123271821 is an equidigital number, since it uses as much as digits as its factorization.

123271821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4565632 (or 4565626 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 123271821 is about 11102.7843805056. The cubic root of 123271821 is about 497.6850599796.

The spelling of 123271821 in words is "one hundred twenty-three million, two hundred seventy-one thousand, eight hundred twenty-one".