21067531 has 2 divisors, whose sum is σ = 21067532. Its totient is φ = 21067530.

The previous prime is 21067513. The next prime is 21067537. The reversal of 21067531 is 13576012.

Together with previous prime (21067513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21067531 - 2⁵ = 21067499 is a prime.

It is a super-2 number, since 2×21067531² = 887681724871922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21067496 and 21067505.

It is not a weakly prime, because it can be changed into another prime (21067537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10533765 + 10533766.

It is an arithmetic number, because the mean of its divisors is an integer number (10533766).

Almost surely, 2^21067531 is an apocalyptic number.

21067531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21067531 is an equidigital number, since it uses as much as digits as its factorization.

21067531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 21067531 is about 4589.9380170107. The cubic root of 21067531 is about 276.1878359745.

The spelling of 21067531 in words is "twenty-one million, sixty-seven thousand, five hundred thirty-one".