21416725 has 24 divisors (see below), whose sum is σ = 29605248. Its totient is φ = 15235200.

The previous prime is 21416713. The next prime is 21416729. The reversal of 21416725 is 52761412.

It is not a de Polignac number, because 21416725 - 2⁷ = 21416597 is a prime.

It is a super-2 number, since 2×21416725² = 917352219451250, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21416693 and 21416702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21416729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12097 + ... + 13753.

It is an arithmetic number, because the mean of its divisors is an integer number (1233552).

Almost surely, 2^21416725 is an apocalyptic number.

21416725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21416725 is a deficient number, since it is larger than the sum of its proper divisors (8188523).

21416725 is a wasteful number, since it uses less digits than its factorization.

21416725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1725 (or 1720 counting only the distinct ones).

The product of its digits is 3360, while the sum is 28.

The square root of 21416725 is about 4627.8207614384. The cubic root of 21416725 is about 277.7054183376.

It can be divided in two parts, 214 and 16725, that multiplied together give a triangular number (3579150 = T₂₆₇₅).

The spelling of 21416725 in words is "twenty-one million, four hundred sixteen thousand, seven hundred twenty-five".