21587101 has 2 divisors, whose sum is σ = 21587102. Its totient is φ = 21587100.

The previous prime is 21587089. The next prime is 21587131. The reversal of 21587101 is 10178512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15007876 + 6579225 = 3874^2 + 2565^2 .

It is a cyclic number.

It is not a de Polignac number, because 21587101 - 2⁹ = 21586589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21587131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10793550 + 10793551.

It is an arithmetic number, because the mean of its divisors is an integer number (10793551).

Almost surely, 2^21587101 is an apocalyptic number.

It is an amenable number.

21587101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21587101 is an equidigital number, since it uses as much as digits as its factorization.

21587101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 21587101 is about 4646.1920967605. The cubic root of 21587101 is about 278.4398820757.

The spelling of 21587101 in words is "twenty-one million, five hundred eighty-seven thousand, one hundred one".