1621368540 has 432 divisors, whose sum is σ = 5960485440. Its totient is φ = 354816000.

The previous prime is 1621368517. The next prime is 1621368547. The reversal of 1621368540 is 458631261.

It is a happy number.

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 = 1621368495 and 1621368504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621368547) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 10737465 + ... + 10737615.

It is an arithmetic number, because the mean of its divisors is an integer number (13797420).

Almost surely, 2^1621368540 is an apocalyptic number.

1621368540 is a gapful number since it is divisible by the number (10) 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 1621368540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2980242720).

1621368540 is an abundant number, since it is smaller than the sum of its proper divisors (4339116900).

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

1621368540 is a wasteful number, since it uses less digits than its factorization.

1621368540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 1621368540 is about 40266.2208308652. The cubic root of 1621368540 is about 1174.7909185849.

The spelling of 1621368540 in words is "one billion, six hundred twenty-one million, three hundred sixty-eight thousand, five hundred forty".