21700156 has 24 divisors (see below), whose sum is σ = 38918880. Its totient is φ = 10584000.

The previous prime is 21700127. The next prime is 21700169. The reversal of 21700156 is 65100712.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30606 + ... + 31306.

It is an arithmetic number, because the mean of its divisors is an integer number (1621620).

Almost surely, 2^21700156 is an apocalyptic number.

It is an amenable number.

21700156 is a deficient number, since it is larger than the sum of its proper divisors (17218724).

21700156 is a wasteful number, since it uses less digits than its factorization.

21700156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 885 (or 883 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 21700156 is about 4658.3426237236. The cubic root of 21700156 is about 278.9251136143.

Adding to 21700156 its reverse (65100712), we get a palindrome (86800868).

The spelling of 21700156 in words is "twenty-one million, seven hundred thousand, one hundred fifty-six".