21770505 has 16 divisors (see below), whose sum is σ = 38703360. Its totient is φ = 11610864.

The previous prime is 21770479. The next prime is 21770521. The reversal of 21770505 is 50507712.

It is not a de Polignac number, because 21770505 - 2⁸ = 21770249 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80497 + ... + 80766.

It is an arithmetic number, because the mean of its divisors is an integer number (2418960).

Almost surely, 2^21770505 is an apocalyptic number.

It is an amenable number.

21770505 is a deficient number, since it is larger than the sum of its proper divisors (16932855).

21770505 is a wasteful number, since it uses less digits than its factorization.

21770505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161277 (or 161271 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 27.

The square root of 21770505 is about 4665.8873754089. The cubic root of 21770505 is about 279.2262011095.

The spelling of 21770505 in words is "twenty-one million, seven hundred seventy thousand, five hundred five".