20645677440 has 256 divisors, whose sum is σ = 73370232000. Its totient is φ = 5486690304.

The previous prime is 20645677391. The next prime is 20645677453. The reversal of 20645677440 is 4477654602.

20645677440 is a `hidden beast` number, since 20 + 64 + 567 + 7 + 4 + 4 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5475876 + ... + 5479644.

Almost surely, 2^20645677440 is an apocalyptic number.

20645677440 is a gapful number since it is divisible by the number (20) 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 20645677440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36685116000).

20645677440 is an abundant number, since it is smaller than the sum of its proper divisors (52724554560).

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

20645677440 is a wasteful number, since it uses less digits than its factorization.

20645677440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4114 (or 4096 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 45.

The spelling of 20645677440 in words is "twenty billion, six hundred forty-five million, six hundred seventy-seven thousand, four hundred forty".