20021356 has 6 divisors (see below), whose sum is σ = 35037380. Its totient is φ = 10010676.

The previous prime is 20021341. The next prime is 20021357. The reversal of 20021356 is 65312002.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20021357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2502666 + ... + 2502673.

Almost surely, 2^20021356 is an apocalyptic number.

It is an amenable number.

20021356 is a deficient number, since it is larger than the sum of its proper divisors (15016024).

20021356 is a wasteful number, since it uses less digits than its factorization.

20021356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5005343 (or 5005341 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20021356 is about 4474.5229913366. The cubic root of 20021356 is about 271.5383424623.

Adding to 20021356 its reverse (65312002), we get a palindrome (85333358).

The spelling of 20021356 in words is "twenty million, twenty-one thousand, three hundred fifty-six".