20781522 has 40 divisors (see below), whose sum is σ = 46911216. Its totient is φ = 6875928.

The previous prime is 20781517. The next prime is 20781529. The reversal of 20781522 is 22518702.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20781529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 26013 + ... + 26799.

Almost surely, 2^20781522 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20781522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23455608).

20781522 is an abundant number, since it is smaller than the sum of its proper divisors (26129694).

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

20781522 is a wasteful number, since it uses less digits than its factorization.

20781522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 964 (or 955 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 20781522 is about 4558.6754655272. The cubic root of 20781522 is about 274.9323117153.

It can be divided in two parts, 2078 and 1522, that added together give a square (3600 = 60²).

The spelling of 20781522 in words is "twenty million, seven hundred eighty-one thousand, five hundred twenty-two".