21295537 has 2 divisors, whose sum is σ = 21295538. Its totient is φ = 21295536.

The previous prime is 21295529. The next prime is 21295553. The reversal of 21295537 is 73559212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16451136 + 4844401 = 4056^2 + 2201^2 .

It is a cyclic number.

It is not a de Polignac number, because 21295537 - 2³ = 21295529 is a prime.

It is a super-2 number, since 2×21295537² = 906999792236738, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21295507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10647768 + 10647769.

It is an arithmetic number, because the mean of its divisors is an integer number (10647769).

Almost surely, 2^21295537 is an apocalyptic number.

It is an amenable number.

21295537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21295537 is an equidigital number, since it uses as much as digits as its factorization.

21295537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18900, while the sum is 34.

The square root of 21295537 is about 4614.7087665420. The cubic root of 21295537 is about 277.1806222039.

The spelling of 21295537 in words is "twenty-one million, two hundred ninety-five thousand, five hundred thirty-seven".