20521366 has 4 divisors (see below), whose sum is σ = 30782052. Its totient is φ = 10260682.

The previous prime is 20521339. The next prime is 20521373. The reversal of 20521366 is 66312502.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×20521366² = 842252925011912, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20521366.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5130340 + ... + 5130343.

It is an arithmetic number, because the mean of its divisors is an integer number (7695513).

Almost surely, 2^20521366 is an apocalyptic number.

20521366 is a deficient number, since it is larger than the sum of its proper divisors (10260686).

20521366 is a wasteful number, since it uses less digits than its factorization.

20521366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10260685.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20521366 is about 4530.0514345866. The cubic root of 20521366 is about 273.7802329641.

Adding to 20521366 its reverse (66312502), we get a palindrome (86833868).

The spelling of 20521366 in words is "twenty million, five hundred twenty-one thousand, three hundred sixty-six".