21148787 has 8 divisors (see below), whose sum is σ = 23164272. Its totient is φ = 19148800.

The previous prime is 21148783. The next prime is 21148807. The reversal of 21148787 is 78784112.

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

It is not a de Polignac number, because 21148787 - 2² = 21148783 is a prime.

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 21148787.

It is not an unprimeable number, because it can be changed into a prime (21148783) 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, 914 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (2895534).

Almost surely, 2^21148787 is an apocalyptic number.

21148787 is a deficient number, since it is larger than the sum of its proper divisors (2015485).

21148787 is a wasteful number, since it uses less digits than its factorization.

21148787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7749.

The product of its digits is 25088, while the sum is 38.

The square root of 21148787 is about 4598.7810341437. The cubic root of 21148787 is about 276.5424595286.

It can be divided in two parts, 2114 and 8787, that added together give a palindrome (10901).

The spelling of 21148787 in words is "twenty-one million, one hundred forty-eight thousand, seven hundred eighty-seven".