64989699840 has 1152 divisors, whose sum is σ = 268999557120. Its totient is φ = 14714929152.

The previous prime is 64989699839. The next prime is 64989699889. The reversal of 64989699840 is 4899698946.

It is a happy number.

64989699840 is a `hidden beast` number, since 6 + 498 + 9 + 6 + 9 + 98 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a super-2 number, since 2×64989699840² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 511729857 + ... + 511729983.

It is an arithmetic number, because the mean of its divisors is an integer number (233506560).

Almost surely, 2^64989699840 is an apocalyptic number.

64989699840 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 64989699840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134499778560).

64989699840 is an abundant number, since it is smaller than the sum of its proper divisors (204009857280).

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

64989699840 is a wasteful number, since it uses less digits than its factorization.

64989699840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 241864704, while the sum is 72.

The spelling of 64989699840 in words is "sixty-four billion, nine hundred eighty-nine million, six hundred ninety-nine thousand, eight hundred forty".