20651249 has 8 divisors (see below), whose sum is σ = 21353640. Its totient is φ = 19958400.

The previous prime is 20651237. The next prime is 20651261. The reversal of 20651249 is 94215602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20651237) and next prime (20651261).

It can be written as a sum of positive squares in 4 ways, for example, as 446224 + 20205025 = 668^2 + 4495^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20651249 - 2²⁰ = 19602673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20651149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2159 + ... + 6779.

It is an arithmetic number, because the mean of its divisors is an integer number (2669205).

Almost surely, 2^20651249 is an apocalyptic number.

It is an amenable number.

20651249 is a deficient number, since it is larger than the sum of its proper divisors (702391).

20651249 is a wasteful number, since it uses less digits than its factorization.

20651249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4771.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 20651249 is about 4544.3645320331. The cubic root of 20651249 is about 274.3566182513.

The spelling of 20651249 in words is "twenty million, six hundred fifty-one thousand, two hundred forty-nine".