21791693 has 8 divisors (see below), whose sum is σ = 27168960. Its totient is φ = 16980480.

The previous prime is 21791687. The next prime is 21791699. The reversal of 21791693 is 39619712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21791687) and next prime (21791699).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21791693 - 2⁴ = 21791677 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21791699) 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, 141428 + ... + 141581.

It is an arithmetic number, because the mean of its divisors is an integer number (3396120).

Almost surely, 2^21791693 is an apocalyptic number.

It is an amenable number.

21791693 is a deficient number, since it is larger than the sum of its proper divisors (5377267).

21791693 is a wasteful number, since it uses less digits than its factorization.

21791693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283027.

The product of its digits is 20412, while the sum is 38.

The square root of 21791693 is about 4668.1573452488. The cubic root of 21791693 is about 279.3167567561.

The spelling of 21791693 in words is "twenty-one million, seven hundred ninety-one thousand, six hundred ninety-three".