21021107 has 2 divisors, whose sum is σ = 21021108. Its totient is φ = 21021106.

The previous prime is 21021101. The next prime is 21021127. The reversal of 21021107 is 70112012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21021107 - 2⁶ = 21021043 is a prime.

It is equal to p_1331240 and since 21021107 and 1331240 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021091 and 21021100.

It is not a weakly prime, because it can be changed into another prime (21021101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510553 + 10510554.

It is an arithmetic number, because the mean of its divisors is an integer number (10510554).

Almost surely, 2^21021107 is an apocalyptic number.

21021107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021107 is an equidigital number, since it uses as much as digits as its factorization.

21021107 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21021107 is about 4584.8780790769. The cubic root of 21021107 is about 275.9848194059.

Adding to 21021107 its reverse (70112012), we get a palindrome (91133119).

The spelling of 21021107 in words is "twenty-one million, twenty-one thousand, one hundred seven".