20867661 has 12 divisors (see below), whose sum is σ = 30181788. Its totient is φ = 13893504.

The previous prime is 20867603. The next prime is 20867663. The reversal of 20867661 is 16676802.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10017225 + 10850436 = 3165^2 + 3294^2 .

It is not a de Polignac number, because 20867661 - 2¹⁴ = 20851277 is a prime.

It is a super-2 number, since 2×20867661² = 870918551221842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20867663) 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, 12661 + ... + 14213.

It is an arithmetic number, because the mean of its divisors is an integer number (2515149).

Almost surely, 2^20867661 is an apocalyptic number.

It is an amenable number.

20867661 is a deficient number, since it is larger than the sum of its proper divisors (9314127).

20867661 is a wasteful number, since it uses less digits than its factorization.

20867661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3052 (or 3049 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 20867661 is about 4568.1135055951. The cubic root of 20867661 is about 275.3116510874.

It can be divided in two parts, 20867 and 661, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20867661 in words is "twenty million, eight hundred sixty-seven thousand, six hundred sixty-one".