21387046 has 16 divisors (see below), whose sum is σ = 34248960. Its totient is φ = 9986760.

The previous prime is 21387001. The next prime is 21387059. The reversal of 21387046 is 64078312.

It is a super-2 number, since 2×21387046² = 914811473212232, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21386999 and 21387017.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1266 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (2140560).

Almost surely, 2^21387046 is an apocalyptic number.

21387046 is a deficient number, since it is larger than the sum of its proper divisors (12861914).

21387046 is a wasteful number, since it uses less digits than its factorization.

21387046 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8019.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21387046 is about 4624.6130648953. The cubic root of 21387046 is about 277.5770789320.

The spelling of 21387046 in words is "twenty-one million, three hundred eighty-seven thousand, forty-six".