20961986 has 8 divisors (see below), whose sum is σ = 33292620. Its totient is φ = 9864448.

The previous prime is 20961961. The next prime is 20962013. The reversal of 20961986 is 68916902.

It can be written as a sum of positive squares in 2 ways, for example, as 19971961 + 990025 = 4469^2 + 995^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308231 + ... + 308298.

Almost surely, 2^20961986 is an apocalyptic number.

20961986 is a deficient number, since it is larger than the sum of its proper divisors (12330634).

20961986 is a wasteful number, since it uses less digits than its factorization.

20961986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616548.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 20961986 is about 4578.4261487983. The cubic root of 20961986 is about 275.7258444790.

The spelling of 20961986 in words is "twenty million, nine hundred sixty-one thousand, nine hundred eighty-six".