20993437 has 2 divisors, whose sum is σ = 20993438. Its totient is φ = 20993436.

The previous prime is 20993431. The next prime is 20993447. The reversal of 20993437 is 73439902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18844281 + 2149156 = 4341^2 + 1466^2 .

It is a cyclic number.

It is not a de Polignac number, because 20993437 - 2¹⁵ = 20960669 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20993396 and 20993405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20993431) 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, 10496718 + 10496719.

It is an arithmetic number, because the mean of its divisors is an integer number (10496719).

Almost surely, 2^20993437 is an apocalyptic number.

It is an amenable number.

20993437 is a deficient number, since it is larger than the sum of its proper divisors (1).

20993437 is an equidigital number, since it uses as much as digits as its factorization.

20993437 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 37.

The square root of 20993437 is about 4581.8595569921. The cubic root of 20993437 is about 275.8636736604.

The spelling of 20993437 in words is "twenty million, nine hundred ninety-three thousand, four hundred thirty-seven".