21151783 has 2 divisors, whose sum is σ = 21151784. Its totient is φ = 21151782.

The previous prime is 21151747. The next prime is 21151787. The reversal of 21151783 is 38715112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21151783 - 2⁹ = 21151271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21151787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575891 + 10575892.

It is an arithmetic number, because the mean of its divisors is an integer number (10575892).

Almost surely, 2^21151783 is an apocalyptic number.

21151783 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151783 is an equidigital number, since it uses as much as digits as its factorization.

21151783 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 28.

The square root of 21151783 is about 4599.1067611005. The cubic root of 21151783 is about 276.5555175208. Note that the first 4 decimals are identical.

Adding to 21151783 its reverse (38715112), we get a palindrome (59866895).

It can be divided in two parts, 211517 and 83, that added together give a square (211600 = 460²).

The spelling of 21151783 in words is "twenty-one million, one hundred fifty-one thousand, seven hundred eighty-three".