857100421 has 4 divisors (see below), whose sum is σ = 857168032. Its totient is φ = 857032812.

The previous prime is 857100323. The next prime is 857100457. The reversal of 857100421 is 124001758.

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 a brilliant number, because the two primes have the same length.

It is a 3-Lehmer number, since φ(857100421) divides (857100421-1)³.

It is a cyclic number.

It is not a de Polignac number, because 857100421 - 2⁹ = 857099909 is a prime.

It is a super-2 number, since 2×857100421² = 1469242263356754482, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 857100421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857100721) 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, 8451 + ... + 42256.

It is an arithmetic number, because the mean of its divisors is an integer number (214292008).

It is a Poulet number, since it divides 2^857100420-1.

Almost surely, 2^857100421 is an apocalyptic number.

857100421 is the 16903-rd octagonal number.

It is an amenable number.

857100421 is a deficient number, since it is larger than the sum of its proper divisors (67611).

857100421 is a wasteful number, since it uses less digits than its factorization.

857100421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67610.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 857100421 is about 29276.2774443747. The cubic root of 857100421 is about 949.8985749522.

The spelling of 857100421 in words is "eight hundred fifty-seven million, one hundred thousand, four hundred twenty-one".