21098647 has 2 divisors, whose sum is σ = 21098648. Its totient is φ = 21098646.

The previous prime is 21098639. The next prime is 21098653. The reversal of 21098647 is 74689012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21098647 - 2³ = 21098639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21098617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549323 + 10549324.

It is an arithmetic number, because the mean of its divisors is an integer number (10549324).

Almost surely, 2^21098647 is an apocalyptic number.

21098647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21098647 is an equidigital number, since it uses as much as digits as its factorization.

21098647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21098647 is about 4593.3263546149. The cubic root of 21098647 is about 276.3237423167.

The spelling of 21098647 in words is "twenty-one million, ninety-eight thousand, six hundred forty-seven".