21742501 has 8 divisors (see below), whose sum is σ = 24484608. Its totient is φ = 19128000.

The previous prime is 21742493. The next prime is 21742571. The reversal of 21742501 is 10524712.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21742501 - 2³ = 21742493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31540 + ... + 32221.

It is an arithmetic number, because the mean of its divisors is an integer number (3060576).

Almost surely, 2^21742501 is an apocalyptic number.

It is an amenable number.

21742501 is a deficient number, since it is larger than the sum of its proper divisors (2742107).

21742501 is a wasteful number, since it uses less digits than its factorization.

21742501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63803.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21742501 is about 4662.8854800434. The cubic root of 21742501 is about 279.1064242872.

The spelling of 21742501 in words is "twenty-one million, seven hundred forty-two thousand, five hundred one".