21372089 has 2 divisors, whose sum is σ = 21372090. Its totient is φ = 21372088.

The previous prime is 21372079. The next prime is 21372103. The reversal of 21372089 is 98027312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21114025 + 258064 = 4595^2 + 508^2 .

It is a cyclic number.

It is not a de Polignac number, because 21372089 - 2¹² = 21367993 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21372019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686044 + 10686045.

It is an arithmetic number, because the mean of its divisors is an integer number (10686045).

Almost surely, 2^21372089 is an apocalyptic number.

It is an amenable number.

21372089 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372089 is an equidigital number, since it uses as much as digits as its factorization.

21372089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21372089 is about 4622.9956738029. The cubic root of 21372089 is about 277.5123561308.

The spelling of 21372089 in words is "twenty-one million, three hundred seventy-two thousand, eighty-nine".