20981701 has 16 divisors (see below), whose sum is σ = 23431408. Its totient is φ = 18662400.

The previous prime is 20981677. The next prime is 20981711. The reversal of 20981701 is 10718902.

It can be written as a sum of positive squares in 8 ways, for example, as 641601 + 20340100 = 801^2 + 4510^2 .

It is a 5-Lehmer number, since φ(20981701) divides (20981701-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 20981701 - 2⁷ = 20981573 is a prime.

It is a deceptive number, since it divides R_20981700.

It is a self number, because there is not a number n which added to its sum of digits gives 20981701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981711) 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, 86941 + ... + 87181.

It is an arithmetic number, because the mean of its divisors is an integer number (1464463).

Almost surely, 2^20981701 is an apocalyptic number.

It is an amenable number.

20981701 is a deficient number, since it is larger than the sum of its proper divisors (2449707).

20981701 is a wasteful number, since it uses less digits than its factorization.

20981701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20981701 is about 4580.5786752331. The cubic root of 20981701 is about 275.8122585514.

The spelling of 20981701 in words is "twenty million, nine hundred eighty-one thousand, seven hundred one".