21142973 has 2 divisors, whose sum is σ = 21142974. Its totient is φ = 21142972.

The previous prime is 21142969. The next prime is 21142981. The reversal of 21142973 is 37924112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 1369 = 4598^2 + 37^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142973 - 2² = 21142969 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21142963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571486 + 10571487.

It is an arithmetic number, because the mean of its divisors is an integer number (10571487).

Almost surely, 2^21142973 is an apocalyptic number.

It is an amenable number.

21142973 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142973 is an equidigital number, since it uses as much as digits as its factorization.

21142973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 21142973 is about 4598.1488666636. The cubic root of 21142973 is about 276.5171158337.

The spelling of 21142973 in words is "twenty-one million, one hundred forty-two thousand, nine hundred seventy-three".