21934487 has 4 divisors (see below), whose sum is σ = 21944280. Its totient is φ = 21924696.

The previous prime is 21934483. The next prime is 21934499. The reversal of 21934487 is 78443912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21934487 - 2² = 21934483 is a prime.

It is a super-2 number, since 2×21934487² = 962243439906338, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21934487.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21934483) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308 + ... + 6630.

It is an arithmetic number, because the mean of its divisors is an integer number (5486070).

Almost surely, 2^21934487 is an apocalyptic number.

21934487 is a deficient number, since it is larger than the sum of its proper divisors (9793).

21934487 is an equidigital number, since it uses as much as digits as its factorization.

21934487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9792.

The product of its digits is 48384, while the sum is 38.

The square root of 21934487 is about 4683.4268436691. The cubic root of 21934487 is about 279.9255201561.

The spelling of 21934487 in words is "twenty-one million, nine hundred thirty-four thousand, four hundred eighty-seven".