21062857 has 8 divisors (see below), whose sum is σ = 22068992. Its totient is φ = 20077200.

The previous prime is 21062851. The next prime is 21062869. The reversal of 21062857 is 75826012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21062857 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21062851) 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, 2994 + ... + 7147.

It is an arithmetic number, because the mean of its divisors is an integer number (2758624).

Almost surely, 2^21062857 is an apocalyptic number.

It is an amenable number.

21062857 is a deficient number, since it is larger than the sum of its proper divisors (1006135).

21062857 is a wasteful number, since it uses less digits than its factorization.

21062857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10239.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 21062857 is about 4589.4288315650. The cubic root of 21062857 is about 276.1674096382.

Adding to 21062857 its reverse (75826012), we get a palindrome (96888869).

The spelling of 21062857 in words is "twenty-one million, sixty-two thousand, eight hundred fifty-seven".