21078371 has 2 divisors, whose sum is σ = 21078372. Its totient is φ = 21078370.

The previous prime is 21078361. The next prime is 21078403. The reversal of 21078371 is 17387012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21078371 - 2⁶ = 21078307 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21078341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10539185 + 10539186.

It is an arithmetic number, because the mean of its divisors is an integer number (10539186).

Almost surely, 2^21078371 is an apocalyptic number.

21078371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21078371 is an equidigital number, since it uses as much as digits as its factorization.

21078371 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 21078371 is about 4591.1187089859. The cubic root of 21078371 is about 276.2351973668.

The spelling of 21078371 in words is "twenty-one million, seventy-eight thousand, three hundred seventy-one".