651581440 has 192 divisors, whose sum is σ = 1751349600. Its totient is φ = 231211008.

The previous prime is 651581419. The next prime is 651581449. The reversal of 651581440 is 44185156.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 651581396 and 651581405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651581449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3307422 + ... + 3307618.

Almost surely, 2^651581440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 651581440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (875674800).

651581440 is an abundant number, since it is smaller than the sum of its proper divisors (1099768160).

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

651581440 is a wasteful number, since it uses less digits than its factorization.

651581440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 34.

The square root of 651581440 is about 25526.0933164478. The cubic root of 651581440 is about 866.9410518455.

It can be divided in two parts, 6515 and 81440, that multiplied together give a triangular number (530581600 = T₃₂₅₇₅).

The spelling of 651581440 in words is "six hundred fifty-one million, five hundred eighty-one thousand, four hundred forty".