21387416 has 16 divisors (see below), whose sum is σ = 40314240. Its totient is φ = 10636960.

The previous prime is 21387409. The next prime is 21387419. The reversal of 21387416 is 61478312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21387419) 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, 5471 + ... + 8526.

It is an arithmetic number, because the mean of its divisors is an integer number (2519640).

Almost surely, 2^21387416 is an apocalyptic number.

It is an amenable number.

21387416 is a deficient number, since it is larger than the sum of its proper divisors (18926824).

21387416 is a wasteful number, since it uses less digits than its factorization.

21387416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14194 (or 14190 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 21387416 is about 4624.6530680690. The cubic root of 21387416 is about 277.5786796350.

The spelling of 21387416 in words is "twenty-one million, three hundred eighty-seven thousand, four hundred sixteen".