21361619 has 2 divisors, whose sum is σ = 21361620. Its totient is φ = 21361618.

The previous prime is 21361609. The next prime is 21361709. The reversal of 21361619 is 91616312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21361619 - 2¹⁶ = 21296083 is a prime.

It is a super-2 number, since 2×21361619² = 912637532602322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21361591 and 21361600.

It is not a weakly prime, because it can be changed into another prime (21361609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10680809 + 10680810.

It is an arithmetic number, because the mean of its divisors is an integer number (10680810).

Almost surely, 2^21361619 is an apocalyptic number.

21361619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21361619 is an equidigital number, since it uses as much as digits as its factorization.

21361619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 29.

The square root of 21361619 is about 4621.8631524527. The cubic root of 21361619 is about 277.4670317677.

The spelling of 21361619 in words is "twenty-one million, three hundred sixty-one thousand, six hundred nineteen".