20571538 has 16 divisors (see below), whose sum is σ = 34304256. Its totient is φ = 9187920.

The previous prime is 20571533. The next prime is 20571539. The reversal of 20571538 is 83517502.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (20571533) 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 7 ways as a sum of consecutive naturals, for example, 11956 + ... + 13567.

It is an arithmetic number, because the mean of its divisors is an integer number (2144016).

Almost surely, 2^20571538 is an apocalyptic number.

20571538 is a deficient number, since it is larger than the sum of its proper divisors (13732718).

20571538 is a wasteful number, since it uses less digits than its factorization.

20571538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25569.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 20571538 is about 4535.5857394608. The cubic root of 20571538 is about 274.0031700843.

The spelling of 20571538 in words is "twenty million, five hundred seventy-one thousand, five hundred thirty-eight".