21741987 has 8 divisors (see below), whose sum is σ = 29010960. Its totient is φ = 14483840.

The previous prime is 21741983. The next prime is 21741989. The reversal of 21741987 is 78914712.

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

It is a cyclic number.

It is not a de Polignac number, because 21741987 - 2² = 21741983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21741983) 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, 5839 + ... + 8807.

It is an arithmetic number, because the mean of its divisors is an integer number (3626370).

Almost surely, 2^21741987 is an apocalyptic number.

21741987 is a deficient number, since it is larger than the sum of its proper divisors (7268973).

21741987 is a wasteful number, since it uses less digits than its factorization.

21741987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5413.

The product of its digits is 28224, while the sum is 39.

The square root of 21741987 is about 4662.8303636311. The cubic root of 21741987 is about 279.1042248801.

The spelling of 21741987 in words is "twenty-one million, seven hundred forty-one thousand, nine hundred eighty-seven".