21537029 has 2 divisors, whose sum is σ = 21537030. Its totient is φ = 21537028.

The previous prime is 21537001. The next prime is 21537049. The reversal of 21537029 is 92073512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10876804 + 10660225 = 3298^2 + 3265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21537029 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21536992 and 21537010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21537049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10768514 + 10768515.

It is an arithmetic number, because the mean of its divisors is an integer number (10768515).

Almost surely, 2^21537029 is an apocalyptic number.

It is an amenable number.

21537029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21537029 is an equidigital number, since it uses as much as digits as its factorization.

21537029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 21537029 is about 4640.8004697466. The cubic root of 21537029 is about 278.2244318806.

The spelling of 21537029 in words is "twenty-one million, five hundred thirty-seven thousand, twenty-nine".