21724309425 has 96 divisors (see below), whose sum is σ = 45632634880. Its totient is φ = 8871379200.

The previous prime is 21724309421. The next prime is 21724309489. The reversal of 21724309425 is 52490342712.

It is not a de Polignac number, because 21724309425 - 2² = 21724309421 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (21724309421) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 160236 + ... + 262914.

Almost surely, 2^21724309425 is an apocalyptic number.

21724309425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21724309425 is an abundant number, since it is smaller than the sum of its proper divisors (23908325455).

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

21724309425 is a wasteful number, since it uses less digits than its factorization.

21724309425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102743 (or 102738 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The spelling of 21724309425 in words is "twenty-one billion, seven hundred twenty-four million, three hundred nine thousand, four hundred twenty-five".