20701581 has 4 divisors (see below), whose sum is σ = 27602112. Its totient is φ = 13801052.

The previous prime is 20701579. The next prime is 20701609. The reversal of 20701581 is 18510702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20701581 - 2¹ = 20701579 is a prime.

It is a super-2 number, since 2×20701581² = 857110911799122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20701511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3450261 + ... + 3450266.

It is an arithmetic number, because the mean of its divisors is an integer number (6900528).

Almost surely, 2^20701581 is an apocalyptic number.

It is an amenable number.

20701581 is a deficient number, since it is larger than the sum of its proper divisors (6900531).

20701581 is an equidigital number, since it uses as much as digits as its factorization.

20701581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6900530.

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 20701581 is about 4549.8990098682. The cubic root of 20701581 is about 274.5793281697.

The spelling of 20701581 in words is "twenty million, seven hundred one thousand, five hundred eighty-one".