21691514 has 16 divisors (see below), whose sum is σ = 35176680. Its totient is φ = 9972480.

The previous prime is 21691513. The next prime is 21691517. The reversal of 21691514 is 41519612.

It can be written as a sum of positive squares in 4 ways, for example, as 9406489 + 12285025 = 3067^2 + 3505^2 .

It is a super-2 number, since 2×21691514² = 941043559224392, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21691513) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5822 + ... + 8790.

Almost surely, 2^21691514 is an apocalyptic number.

21691514 is a deficient number, since it is larger than the sum of its proper divisors (13485166).

21691514 is a wasteful number, since it uses less digits than its factorization.

21691514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3265.

The product of its digits is 2160, while the sum is 29.

The square root of 21691514 is about 4657.4149482304. The cubic root of 21691514 is about 278.8880817624. Note that the first 3 decimals are identical.

The spelling of 21691514 in words is "twenty-one million, six hundred ninety-one thousand, five hundred fourteen".