21170919 has 32 divisors (see below), whose sum is σ = 36158976. Its totient is φ = 10696320.

The previous prime is 21170917. The next prime is 21170969. The reversal of 21170919 is 91907112.

It is not a de Polignac number, because 21170919 - 2¹ = 21170917 is a prime.

It is a super-2 number, since 2×21170919² = 896415622609122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170917) 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, 7309 + ... + 9785.

It is an arithmetic number, because the mean of its divisors is an integer number (1129968).

Almost surely, 2^21170919 is an apocalyptic number.

21170919 is a deficient number, since it is larger than the sum of its proper divisors (14988057).

21170919 is a wasteful number, since it uses less digits than its factorization.

21170919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2535.

The product of its (nonzero) digits is 1134, while the sum is 30.

The square root of 21170919 is about 4601.1866947560. The cubic root of 21170919 is about 276.6388922297.

The spelling of 21170919 in words is "twenty-one million, one hundred seventy thousand, nine hundred nineteen".