20653531 has 4 divisors (see below), whose sum is σ = 20866552. Its totient is φ = 20440512.

The previous prime is 20653519. The next prime is 20653537. The reversal of 20653531 is 13535602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13535602 = 2 ⋅6767801.

It is a cyclic number.

It is not a de Polignac number, because 20653531 - 2⁵ = 20653499 is a prime.

It is a super-2 number, since 2×20653531² = 853136685535922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20653496 and 20653505.

It is not an unprimeable number, because it can be changed into a prime (20653537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106365 + ... + 106558.

It is an arithmetic number, because the mean of its divisors is an integer number (5216638).

Almost surely, 2^20653531 is an apocalyptic number.

20653531 is a deficient number, since it is larger than the sum of its proper divisors (213021).

20653531 is an equidigital number, since it uses as much as digits as its factorization.

20653531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213020.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 20653531 is about 4544.6156053070. The cubic root of 20653531 is about 274.3667235116.

The spelling of 20653531 in words is "twenty million, six hundred fifty-three thousand, five hundred thirty-one".