21347788 has 36 divisors (see below), whose sum is σ = 46937296. Its totient is φ = 8316000.

The previous prime is 21347771. The next prime is 21347791. The reversal of 21347788 is 88774312.

It is a self number, because there is not a number n which added to its sum of digits gives 21347788.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 238 + ... + 6538.

Almost surely, 2^21347788 is an apocalyptic number.

21347788 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21347788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23468648).

21347788 is an abundant number, since it is smaller than the sum of its proper divisors (25589508).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21347788 is a wasteful number, since it uses less digits than its factorization.

21347788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6334 (or 6321 counting only the distinct ones).

The product of its digits is 75264, while the sum is 40.

The square root of 21347788 is about 4620.3666521176. The cubic root of 21347788 is about 277.4071350113.

The spelling of 21347788 in words is "twenty-one million, three hundred forty-seven thousand, seven hundred eighty-eight".