21311719 has 8 divisors (see below), whose sum is σ = 25037712. Its totient is φ = 17883840.

The previous prime is 21311701. The next prime is 21311729. The reversal of 21311719 is 91711312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21311719 - 2¹¹ = 21309671 is a prime.

It is a super-2 number, since 2×21311719² = 908378733469922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21311693 and 21311702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74374 + ... + 74659.

It is an arithmetic number, because the mean of its divisors is an integer number (3129714).

Almost surely, 2^21311719 is an apocalyptic number.

21311719 is a deficient number, since it is larger than the sum of its proper divisors (3725993).

21311719 is a wasteful number, since it uses less digits than its factorization.

21311719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149057.

The product of its digits is 378, while the sum is 25.

The square root of 21311719 is about 4616.4617403375. The cubic root of 21311719 is about 277.2508122036.

The spelling of 21311719 in words is "twenty-one million, three hundred eleven thousand, seven hundred nineteen".