21151061 has 2 divisors, whose sum is σ = 21151062. Its totient is φ = 21151060.

The previous prime is 21151057. The next prime is 21151069. The reversal of 21151061 is 16015112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21104836 + 46225 = 4594^2 + 215^2 .

It is a cyclic number.

It is not a de Polignac number, because 21151061 - 2² = 21151057 is a prime.

It is a zygodrome in base 4.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21151069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575530 + 10575531.

It is an arithmetic number, because the mean of its divisors is an integer number (10575531).

Almost surely, 2^21151061 is an apocalyptic number.

It is an amenable number.

21151061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151061 is an equidigital number, since it uses as much as digits as its factorization.

21151061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60, while the sum is 17.

The square root of 21151061 is about 4599.0282669277. The cubic root of 21151061 is about 276.5523708144.

Adding to 21151061 its reverse (16015112), we get a palindrome (37166173).

The spelling of 21151061 in words is "twenty-one million, one hundred fifty-one thousand, sixty-one".