16251021 has 12 divisors (see below), whose sum is σ = 23534940. Its totient is φ = 10805760.

The previous prime is 16251017. The next prime is 16251043. The reversal of 16251021 is 12015261.

It can be written as a sum of positive squares in 2 ways, for example, as 6702921 + 9548100 = 2589^2 + 3090^2 .

It is not a de Polignac number, because 16251021 - 2² = 16251017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16250985 and 16251003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16231021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1645 + ... + 5933.

It is an arithmetic number, because the mean of its divisors is an integer number (1961245).

Almost surely, 2^16251021 is an apocalyptic number.

It is an amenable number.

16251021 is a deficient number, since it is larger than the sum of its proper divisors (7283919).

16251021 is a wasteful number, since it uses less digits than its factorization.

16251021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4716 (or 4713 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 16251021 is about 4031.2555116241. The cubic root of 16251021 is about 253.2951556427.

Adding to 16251021 its reverse (12015261), we get a palindrome (28266282).

The spelling of 16251021 in words is "sixteen million, two hundred fifty-one thousand, twenty-one".