21877487 has 8 divisors (see below), whose sum is σ = 23220432. Its totient is φ = 20540800.

The previous prime is 21877483. The next prime is 21877489. The reversal of 21877487 is 78477812.

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 21877487 - 2² = 21877483 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21877483) 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, 7037 + ... + 9657.

It is an arithmetic number, because the mean of its divisors is an integer number (2902554).

Almost surely, 2^21877487 is an apocalyptic number.

21877487 is a deficient number, since it is larger than the sum of its proper divisors (1342945).

21877487 is a wasteful number, since it uses less digits than its factorization.

21877487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3129.

The product of its digits is 175616, while the sum is 44.

The square root of 21877487 is about 4677.3375973945. The cubic root of 21877487 is about 279.6828338974.

The spelling of 21877487 in words is "twenty-one million, eight hundred seventy-seven thousand, four hundred eighty-seven".