21745078 has 4 divisors (see below), whose sum is σ = 32617620. Its totient is φ = 10872538.

The previous prime is 21745069. The next prime is 21745081. The reversal of 21745078 is 87054712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5436268 + ... + 5436271.

It is an arithmetic number, because the mean of its divisors is an integer number (8154405).

Almost surely, 2^21745078 is an apocalyptic number.

21745078 is a deficient number, since it is larger than the sum of its proper divisors (10872542).

21745078 is a wasteful number, since it uses less digits than its factorization.

21745078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10872541.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 21745078 is about 4663.1618028973. The cubic root of 21745078 is about 279.1174507532.

The spelling of 21745078 in words is "twenty-one million, seven hundred forty-five thousand, seventy-eight".