20661894 has 48 divisors (see below), whose sum is σ = 49153104. Its totient is φ = 6220800.

The previous prime is 20661881. The next prime is 20661913. The reversal of 20661894 is 49816602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47502 + ... + 47934.

It is an arithmetic number, because the mean of its divisors is an integer number (1024023).

Almost surely, 2^20661894 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20661894, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24576552).

20661894 is an abundant number, since it is smaller than the sum of its proper divisors (28491210).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20661894 is a wasteful number, since it uses less digits than its factorization.

20661894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 20661894 is about 4545.5356120044. The cubic root of 20661894 is about 274.4037505827.

The spelling of 20661894 in words is "twenty million, six hundred sixty-one thousand, eight hundred ninety-four".