21071719 has 4 divisors (see below), whose sum is σ = 21798360. Its totient is φ = 20345080.

The previous prime is 21071717. The next prime is 21071737. The reversal of 21071719 is 91717012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21071719 - 2¹ = 21071717 is a prime.

It is a super-2 number, since 2×21071719² = 888034683229922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363277 + ... + 363334.

It is an arithmetic number, because the mean of its divisors is an integer number (5449590).

Almost surely, 2^21071719 is an apocalyptic number.

21071719 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21071719 is a deficient number, since it is larger than the sum of its proper divisors (726641).

21071719 is an equidigital number, since it uses as much as digits as its factorization.

21071719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726640.

The product of its (nonzero) digits is 882, while the sum is 28.

The square root of 21071719 is about 4590.3942096513. The cubic root of 21071719 is about 276.2061358253.

The spelling of 21071719 in words is "twenty-one million, seventy-one thousand, seven hundred nineteen".