20439531 has 12 divisors (see below), whose sum is σ = 33741552. Its totient is φ = 11679696.

The previous prime is 20439493. The next prime is 20439541. The reversal of 20439531 is 13593402.

It is not a de Polignac number, because 20439531 - 2¹⁴ = 20423147 is a prime.

It is a super-2 number, since 2×20439531² = 835548854999922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20439495 and 20439504.

It is not an unprimeable number, because it can be changed into a prime (20439541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162156 + ... + 162281.

It is an arithmetic number, because the mean of its divisors is an integer number (2811796).

Almost surely, 2^20439531 is an apocalyptic number.

20439531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20439531 is a deficient number, since it is larger than the sum of its proper divisors (13302021).

20439531 is a wasteful number, since it uses less digits than its factorization.

20439531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324450 (or 324447 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 20439531 is about 4521.0099535391. The cubic root of 20439531 is about 273.4158216566.

The spelling of 20439531 in words is "twenty million, four hundred thirty-nine thousand, five hundred thirty-one".