21501131 has 2 divisors, whose sum is σ = 21501132. Its totient is φ = 21501130.

The previous prime is 21501121. The next prime is 21501187. The reversal of 21501131 is 13110512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21501131 - 2¹⁴ = 21484747 is a prime.

It is a super-2 number, since 2×21501131² = 924597268558322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21501101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750565 + 10750566.

It is an arithmetic number, because the mean of its divisors is an integer number (10750566).

Almost surely, 2^21501131 is an apocalyptic number.

21501131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21501131 is an equidigital number, since it uses as much as digits as its factorization.

21501131 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30, while the sum is 14.

The square root of 21501131 is about 4636.9312050105. The cubic root of 21501131 is about 278.0697640761.

Adding to 21501131 its reverse (13110512), we get a palindrome (34611643).

The spelling of 21501131 in words is "twenty-one million, five hundred one thousand, one hundred thirty-one".