20747657 has 4 divisors (see below), whose sum is σ = 23711616. Its totient is φ = 17783700.

The previous prime is 20747653. The next prime is 20747663. The reversal of 20747657 is 75674702.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75674702 = 2 ⋅37837351.

It is a cyclic number.

It is not a de Polignac number, because 20747657 - 2² = 20747653 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20747657.

It is not an unprimeable number, because it can be changed into a prime (20747653) 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, 1481969 + ... + 1481982.

It is an arithmetic number, because the mean of its divisors is an integer number (5927904).

Almost surely, 2^20747657 is an apocalyptic number.

It is an amenable number.

20747657 is a deficient number, since it is larger than the sum of its proper divisors (2963959).

20747657 is an equidigital number, since it uses as much as digits as its factorization.

20747657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2963958.

The product of its (nonzero) digits is 82320, while the sum is 38.

The square root of 20747657 is about 4554.9596046507. The cubic root of 20747657 is about 274.7828897954.

It can be divided in two parts, 2074765 and 7, that multiplied together give a triangular number (14523355 = T₅₃₈₉).

The spelling of 20747657 in words is "twenty million, seven hundred forty-seven thousand, six hundred fifty-seven".