51786990 has 48 divisors (see below), whose sum is σ = 135907200. Its totient is φ = 13680576.

The previous prime is 51786983. The next prime is 51786991. The reversal of 51786990 is 9968715.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51786991) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7171 + ... + 12449.

It is an arithmetic number, because the mean of its divisors is an integer number (2831400).

Almost surely, 2^51786990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51786990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67953600).

51786990 is an abundant number, since it is smaller than the sum of its proper divisors (84120210).

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

51786990 is a wasteful number, since it uses less digits than its factorization.

51786990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401 (or 5398 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 51786990 is about 7196.3178084351. The cubic root of 51786990 is about 372.7407629282.

It can be divided in two parts, 5 and 1786990, that added together give a triangular number (1786995 = T₁₈₉₀).

The spelling of 51786990 in words is "fifty-one million, seven hundred eighty-six thousand, nine hundred ninety".