20994487 has 16 divisors (see below), whose sum is σ = 22809600. Its totient is φ = 19262880.

The previous prime is 20994451. The next prime is 20994509. The reversal of 20994487 is 78449902.

It is a cyclic number.

It is not a de Polignac number, because 20994487 - 2¹⁵ = 20961719 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20994437) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106473 + ... + 106669.

It is an arithmetic number, because the mean of its divisors is an integer number (1425600).

Almost surely, 2^20994487 is an apocalyptic number.

20994487 is a deficient number, since it is larger than the sum of its proper divisors (1815113).

20994487 is a wasteful number, since it uses less digits than its factorization.

20994487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 20994487 is about 4581.9741378580. The cubic root of 20994487 is about 275.8682727490.

The spelling of 20994487 in words is "twenty million, nine hundred ninety-four thousand, four hundred eighty-seven".