21745707 has 16 divisors (see below), whose sum is σ = 29640960. Its totient is φ = 14176800.

The previous prime is 21745697. The next prime is 21745727. The reversal of 21745707 is 70754712.

It is a happy number.

It is not a de Polignac number, because 21745707 - 2⁶ = 21745643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21745727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60394 + ... + 60752.

It is an arithmetic number, because the mean of its divisors is an integer number (1852560).

Almost surely, 2^21745707 is an apocalyptic number.

21745707 is a deficient number, since it is larger than the sum of its proper divisors (7895253).

21745707 is a wasteful number, since it uses less digits than its factorization.

21745707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754.

The product of its (nonzero) digits is 13720, while the sum is 33.

The square root of 21745707 is about 4663.2292459196. The cubic root of 21745707 is about 279.1201419857.

The spelling of 21745707 in words is "twenty-one million, seven hundred forty-five thousand, seven hundred seven".