21143951 has 2 divisors, whose sum is σ = 21143952. Its totient is φ = 21143950.

The previous prime is 21143921. The next prime is 21143977. The reversal of 21143951 is 15934112.

It is an a-pointer prime, because the next prime (21143977) can be obtained adding 21143951 to its sum of digits (26).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21143951 - 2¹⁸ = 20881807 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21143951.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571975 + 10571976.

It is an arithmetic number, because the mean of its divisors is an integer number (10571976).

Almost surely, 2^21143951 is an apocalyptic number.

21143951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143951 is an equidigital number, since it uses as much as digits as its factorization.

21143951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 26.

The square root of 21143951 is about 4598.2552125779. The cubic root of 21143951 is about 276.5213793396.

The spelling of 21143951 in words is "twenty-one million, one hundred forty-three thousand, nine hundred fifty-one".