21519061 has 2 divisors, whose sum is σ = 21519062. Its totient is φ = 21519060.

The previous prime is 21518971. The next prime is 21519067. The reversal of 21519061 is 16091512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 72900 = 4631^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21519061 - 2⁷ = 21518933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21519067) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10759530 + 10759531.

It is an arithmetic number, because the mean of its divisors is an integer number (10759531).

Almost surely, 2^21519061 is an apocalyptic number.

It is an amenable number.

21519061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21519061 is an equidigital number, since it uses as much as digits as its factorization.

21519061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 25.

The square root of 21519061 is about 4638.8641928817. The cubic root of 21519061 is about 278.1470376175.

The spelling of 21519061 in words is "twenty-one million, five hundred nineteen thousand, sixty-one".