21377428 has 12 divisors (see below), whose sum is σ = 37451680. Its totient is φ = 10676952.

The previous prime is 21377417. The next prime is 21377459. The reversal of 21377428 is 82477312.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21377393 and 21377402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2113 + ... + 6871.

Almost surely, 2^21377428 is an apocalyptic number.

It is an amenable number.

21377428 is a deficient number, since it is larger than the sum of its proper divisors (16074252).

21377428 is a wasteful number, since it uses less digits than its factorization.

21377428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5886 (or 5884 counting only the distinct ones).

The product of its digits is 18816, while the sum is 34.

The square root of 21377428 is about 4623.5730771774. The cubic root of 21377428 is about 277.5354628271.

The spelling of 21377428 in words is "twenty-one million, three hundred seventy-seven thousand, four hundred twenty-eight".