21745004 has 12 divisors (see below), whose sum is σ = 38512824. Its totient is φ = 10741344.

The previous prime is 21745001. The next prime is 21745007. The reversal of 21745004 is 40054712.

It is an interprime number because it is at equal distance from previous prime (21745001) and next prime (21745007).

It is not an unprimeable number, because it can be changed into a prime (21745001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32417 + ... + 33080.

It is an arithmetic number, because the mean of its divisors is an integer number (3209402).

Almost surely, 2^21745004 is an apocalyptic number.

It is an amenable number.

21745004 is a deficient number, since it is larger than the sum of its proper divisors (16767820).

21745004 is a wasteful number, since it uses less digits than its factorization.

21745004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65584 (or 65582 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21745004 is about 4663.1538683599. The cubic root of 21745004 is about 279.1171341342.

Adding to 21745004 its reverse (40054712), we get a palindrome (61799716).

The spelling of 21745004 in words is "twenty-one million, seven hundred forty-five thousand, four".