21541724 has 6 divisors (see below), whose sum is σ = 37698024. Its totient is φ = 10770860.

The previous prime is 21541721. The next prime is 21541727. The reversal of 21541724 is 42714512.

It is an interprime number because it is at equal distance from previous prime (21541721) and next prime (21541727).

It is a junction number, because it is equal to n+sod(n) for n = 21541693 and 21541702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2692712 + ... + 2692719.

It is an arithmetic number, because the mean of its divisors is an integer number (6283004).

Almost surely, 2^21541724 is an apocalyptic number.

It is an amenable number.

21541724 is a deficient number, since it is larger than the sum of its proper divisors (16156300).

21541724 is a wasteful number, since it uses less digits than its factorization.

21541724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5385435 (or 5385433 counting only the distinct ones).

The product of its digits is 2240, while the sum is 26.

The square root of 21541724 is about 4641.3062816410. The cubic root of 21541724 is about 278.2446477423.

The spelling of 21541724 in words is "twenty-one million, five hundred forty-one thousand, seven hundred twenty-four".