20861667 has 24 divisors (see below), whose sum is σ = 32467968. Its totient is φ = 12870000.

The previous prime is 20861663. The next prime is 20861699. The reversal of 20861667 is 76616802.

It is a happy number.

It is not a de Polignac number, because 20861667 - 2² = 20861663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20861663) 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, 4792 + ... + 8042.

It is an arithmetic number, because the mean of its divisors is an integer number (1352832).

Almost surely, 2^20861667 is an apocalyptic number.

20861667 is a deficient number, since it is larger than the sum of its proper divisors (11606301).

20861667 is a wasteful number, since it uses less digits than its factorization.

20861667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3311 (or 3308 counting only the distinct ones).

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

The square root of 20861667 is about 4567.4573889638. The cubic root of 20861667 is about 275.2852885087.

It can be divided in two parts, 20861 and 667, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20861667 in words is "twenty million, eight hundred sixty-one thousand, six hundred sixty-seven".