20778537 has 8 divisors (see below), whose sum is σ = 29835904. Its totient is φ = 12786768.

The previous prime is 20778521. The next prime is 20778551. The reversal of 20778537 is 73587702.

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

It is not a de Polignac number, because 20778537 - 2⁴ = 20778521 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 532783 = 20778537 / (2 + 0 + 7 + 7 + 8 + 5 + 3 + 7).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20778495 and 20778504.

It is not an unprimeable number, because it can be changed into a prime (20778517) 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, 266353 + ... + 266430.

It is an arithmetic number, because the mean of its divisors is an integer number (3729488).

Almost surely, 2^20778537 is an apocalyptic number.

It is an amenable number.

20778537 is a deficient number, since it is larger than the sum of its proper divisors (9057367).

20778537 is a wasteful number, since it uses less digits than its factorization.

20778537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532799.

The product of its (nonzero) digits is 82320, while the sum is 39.

The square root of 20778537 is about 4558.3480560396. The cubic root of 20778537 is about 274.9191475809.

The spelling of 20778537 in words is "twenty million, seven hundred seventy-eight thousand, five hundred thirty-seven".