51620778 has 72 divisors (see below), whose sum is σ = 124550244. Its totient is φ = 15438720.

The previous prime is 51620749. The next prime is 51620813. The reversal of 51620778 is 87702615.

It can be written as a sum of positive squares in 2 ways, for example, as 47568609 + 4052169 = 6897^2 + 2013^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 298300 + ... + 298472.

Almost surely, 2^51620778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51620778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62275122).

51620778 is an abundant number, since it is smaller than the sum of its proper divisors (72929466).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51620778 is a wasteful number, since it uses less digits than its factorization.

51620778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 51620778 is about 7184.7601212567. The cubic root of 51620778 is about 372.3415610744.

The spelling of 51620778 in words is "fifty-one million, six hundred twenty thousand, seven hundred seventy-eight".