20970731 has 8 divisors (see below), whose sum is σ = 21272304. Its totient is φ = 20671200.

The previous prime is 20970709. The next prime is 20970739. The reversal of 20970731 is 13707902.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20970731 - 2⁶ = 20970667 is a prime.

It is a super-2 number, since 2×20970731² = 879543117348722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20970694 and 20970703.

It is not an unprimeable number, because it can be changed into a prime (20970739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39836 + ... + 40358.

It is an arithmetic number, because the mean of its divisors is an integer number (2659038).

Almost surely, 2^20970731 is an apocalyptic number.

20970731 is a deficient number, since it is larger than the sum of its proper divisors (301573).

20970731 is a wasteful number, since it uses less digits than its factorization.

20970731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021.

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 20970731 is about 4579.3810717170. The cubic root of 20970731 is about 275.7641819291.

The spelling of 20970731 in words is "twenty million, nine hundred seventy thousand, seven hundred thirty-one".