21537049 has 2 divisors, whose sum is σ = 21537050. Its totient is φ = 21537048.

The previous prime is 21537029. The next prime is 21537073. The reversal of 21537049 is 94073512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21483225 + 53824 = 4635^2 + 232^2 .

It is a cyclic number.

It is not a de Polignac number, because 21537049 - 2¹¹ = 21535001 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21537049.

It is not a weakly prime, because it can be changed into another prime (21537029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10768524 + 10768525.

It is an arithmetic number, because the mean of its divisors is an integer number (10768525).

Almost surely, 2^21537049 is an apocalyptic number.

It is an amenable number.

21537049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21537049 is an equidigital number, since it uses as much as digits as its factorization.

21537049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21537049 is about 4640.8026245467. The cubic root of 21537049 is about 278.2245180034.

The spelling of 21537049 in words is "twenty-one million, five hundred thirty-seven thousand, forty-nine".