20747557 has 8 divisors (see below), whose sum is σ = 21621600. Its totient is φ = 19884144.

The previous prime is 20747537. The next prime is 20747567. The reversal of 20747557 is 75574702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20747557 is a prime.

It is a super-2 number, since 2×20747557² = 860922242936498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20747537) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1458 + ... + 6604.

It is an arithmetic number, because the mean of its divisors is an integer number (2702700).

Almost surely, 2^20747557 is an apocalyptic number.

It is an amenable number.

20747557 is a deficient number, since it is larger than the sum of its proper divisors (874043).

20747557 is a wasteful number, since it uses less digits than its factorization.

20747557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5315.

The product of its (nonzero) digits is 68600, while the sum is 37.

The square root of 20747557 is about 4554.9486275918. The cubic root of 20747557 is about 274.7824483266.

The spelling of 20747557 in words is "twenty million, seven hundred forty-seven thousand, five hundred fifty-seven".