20857356 has 72 divisors (see below), whose sum is σ = 58216704. Its totient is φ = 6255360.

The previous prime is 20857321. The next prime is 20857357. The reversal of 20857356 is 65375802.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20857356.

It is not an unprimeable number, because it can be changed into a prime (20857357) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18645 + ... + 19731.

Almost surely, 2^20857356 is an apocalyptic number.

20857356 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20857356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29108352).

20857356 is an abundant number, since it is smaller than the sum of its proper divisors (37359348).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20857356 is a wasteful number, since it uses less digits than its factorization.

20857356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1151 (or 1146 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 20857356 is about 4566.9854389958. The cubic root of 20857356 is about 275.2663249134.

The spelling of 20857356 in words is "twenty million, eight hundred fifty-seven thousand, three hundred fifty-six".