20961236 has 6 divisors (see below), whose sum is σ = 36682170. Its totient is φ = 10480616.

The previous prime is 20961181. The next prime is 20961251. The reversal of 20961236 is 63216902.

It can be written as a sum of positive squares in only one way, i.e., 19624900 + 1336336 = 4430^2 + 1156^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20961199 and 20961208.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2620151 + ... + 2620158.

It is an arithmetic number, because the mean of its divisors is an integer number (6113695).

Almost surely, 2^20961236 is an apocalyptic number.

It is an amenable number.

20961236 is a deficient number, since it is larger than the sum of its proper divisors (15720934).

20961236 is a wasteful number, since it uses less digits than its factorization.

20961236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5240313 (or 5240311 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 20961236 is about 4578.3442421906. The cubic root of 20961236 is about 275.7225560366.

The spelling of 20961236 in words is "twenty million, nine hundred sixty-one thousand, two hundred thirty-six".