21724087434 has 32 divisors (see below), whose sum is σ = 51256836096. Its totient is φ = 6006659760.

The previous prime is 21724087433. The next prime is 21724087453. The reversal of 21724087434 is 43478042712.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21724087433) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8341282 + ... + 8343885.

It is an arithmetic number, because the mean of its divisors is an integer number (1601776128).

Almost surely, 2^21724087434 is an apocalyptic number.

21724087434 is an abundant number, since it is smaller than the sum of its proper divisors (29532748662).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21724087434 is a wasteful number, since it uses less digits than its factorization.

21724087434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16685210.

The product of its (nonzero) digits is 301056, while the sum is 42.

The spelling of 21724087434 in words is "twenty-one billion, seven hundred twenty-four million, eighty-seven thousand, four hundred thirty-four".