20615237640 has 192 divisors, whose sum is σ = 71783971200. Its totient is φ = 5252607360.

The previous prime is 20615237623. The next prime is 20615237651. The reversal of 20615237640 is 4673251602.

20615237640 is a `hidden beast` number, since 2 + 0 + 6 + 1 + 5 + 2 + 3 + 7 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20615237595 and 20615237604.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22628785 + ... + 22629695.

It is an arithmetic number, because the mean of its divisors is an integer number (373874850).

Almost surely, 2^20615237640 is an apocalyptic number.

20615237640 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 20615237640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35891985600).

20615237640 is an abundant number, since it is smaller than the sum of its proper divisors (51168733560).

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

20615237640 is an equidigital number, since it uses as much as digits as its factorization.

20615237640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1865 (or 944 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 20615237640 in words is "twenty billion, six hundred fifteen million, two hundred thirty-seven thousand, six hundred forty".