20722646 has 32 divisors (see below), whose sum is σ = 37635840. Its totient is φ = 8368416.

The previous prime is 20722621. The next prime is 20722649. The reversal of 20722646 is 64622702.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20722649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16865 + ... + 18051.

It is an arithmetic number, because the mean of its divisors is an integer number (1176120).

Almost surely, 2^20722646 is an apocalyptic number.

20722646 is a deficient number, since it is larger than the sum of its proper divisors (16913194).

20722646 is a wasteful number, since it uses less digits than its factorization.

20722646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1268.

The product of its (nonzero) digits is 8064, while the sum is 29.

The square root of 20722646 is about 4552.2133078317. The cubic root of 20722646 is about 274.6724297997.

The spelling of 20722646 in words is "twenty million, seven hundred twenty-two thousand, six hundred forty-six".