20661715 has 16 divisors (see below), whose sum is σ = 26867808. Its totient is φ = 15192576.

The previous prime is 20661703. The next prime is 20661727. The reversal of 20661715 is 51716602.

It is an interprime number because it is at equal distance from previous prime (20661703) and next prime (20661727).

It is a cyclic number.

It is not a de Polignac number, because 20661715 - 2⁷ = 20661587 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 829 + ... + 6481.

It is an arithmetic number, because the mean of its divisors is an integer number (1679238).

Almost surely, 2^20661715 is an apocalyptic number.

20661715 is a deficient number, since it is larger than the sum of its proper divisors (6206093).

20661715 is a wasteful number, since it uses less digits than its factorization.

20661715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5718.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 20661715 is about 4545.5159223129. The cubic root of 20661715 is about 274.4029581672.

The spelling of 20661715 in words is "twenty million, six hundred sixty-one thousand, seven hundred fifteen".