20531537 has 8 divisors (see below), whose sum is σ = 22225896. Its totient is φ = 18853632.

The previous prime is 20531521. The next prime is 20531543. The reversal of 20531537 is 73513502.

It can be written as a sum of positive squares in 4 ways, for example, as 5755201 + 14776336 = 2399^2 + 3844^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20531537 - 2⁴ = 20531521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20531437) 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 7 ways as a sum of consecutive naturals, for example, 1448 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (2778237).

Almost surely, 2^20531537 is an apocalyptic number.

It is an amenable number.

20531537 is a deficient number, since it is larger than the sum of its proper divisors (1694359).

20531537 is a wasteful number, since it uses less digits than its factorization.

20531537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8227.

The product of its (nonzero) digits is 3150, while the sum is 26.

The square root of 20531537 is about 4531.1739097060. The cubic root of 20531537 is about 273.8254567052.

The spelling of 20531537 in words is "twenty million, five hundred thirty-one thousand, five hundred thirty-seven".