20993651 has 16 divisors (see below), whose sum is σ = 26131200. Its totient is φ = 16456608.

The previous prime is 20993633. The next prime is 20993663. The reversal of 20993651 is 15639902.

It is not a de Polignac number, because 20993651 - 2¹⁴ = 20977267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20993611) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 1136 + ... + 6578.

It is an arithmetic number, because the mean of its divisors is an integer number (1633200).

Almost surely, 2^20993651 is an apocalyptic number.

20993651 is a deficient number, since it is larger than the sum of its proper divisors (5137549).

20993651 is a wasteful number, since it uses less digits than its factorization.

20993651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5498.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 20993651 is about 4581.8829098963. The cubic root of 20993651 is about 275.8646110109.

The spelling of 20993651 in words is "twenty million, nine hundred ninety-three thousand, six hundred fifty-one".