651421440 has 360 divisors, whose sum is σ = 2392117728. Its totient is φ = 169205760.

The previous prime is 651421411. The next prime is 651421451. The reversal of 651421440 is 44124156.

651421440 is a `hidden beast` number, since 6 + 514 + 2 + 144 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 6324429 + ... + 6324531.

Almost surely, 2^651421440 is an apocalyptic number.

651421440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 651421440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1196058864).

651421440 is an abundant number, since it is smaller than the sum of its proper divisors (1740696288).

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

651421440 is a wasteful number, since it uses less digits than its factorization.

651421440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 651421440 is about 25522.9590760946. The cubic root of 651421440 is about 866.8700850586.

Adding to 651421440 its reverse (44124156), we get a palindrome (695545596).

The spelling of 651421440 in words is "six hundred fifty-one million, four hundred twenty-one thousand, four hundred forty".