21719943 has 24 divisors (see below), whose sum is σ = 36003968. Its totient is φ = 12359952.

The previous prime is 21719941. The next prime is 21719953. The reversal of 21719943 is 34991712.

It is not a de Polignac number, because 21719943 - 2¹ = 21719941 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21719898 and 21719907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21719941) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18780 + ... + 19902.

Almost surely, 2^21719943 is an apocalyptic number.

21719943 is a deficient number, since it is larger than the sum of its proper divisors (14284025).

21719943 is a wasteful number, since it uses less digits than its factorization.

21719943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1443 (or 1440 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 21719943 is about 4660.4659638281. The cubic root of 21719943 is about 279.0098659170.

The spelling of 21719943 in words is "twenty-one million, seven hundred nineteen thousand, nine hundred forty-three".