21702945 has 32 divisors (see below), whose sum is σ = 39112704. Its totient is φ = 10180800.

The previous prime is 21702937. The next prime is 21702949. The reversal of 21702945 is 54920712.

It is not a de Polignac number, because 21702945 - 2³ = 21702937 is a prime.

It is a super-3 number, since 3×21702945³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21702949) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2994 + ... + 7236.

It is an arithmetic number, because the mean of its divisors is an integer number (1222272).

Almost surely, 2^21702945 is an apocalyptic number.

It is an amenable number.

21702945 is a deficient number, since it is larger than the sum of its proper divisors (17409759).

21702945 is a wasteful number, since it uses less digits than its factorization.

21702945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4293.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21702945 is about 4658.6419695014. The cubic root of 21702945 is about 278.9370626654.

It can be divided in two parts, 2170 and 2945, that added together give a palindrome (5115).

The spelling of 21702945 in words is "twenty-one million, seven hundred two thousand, nine hundred forty-five".