1621121040 has 840 divisors, whose sum is σ = 7435827648. Its totient is φ = 319127040.

The previous prime is 1621121009. The next prime is 1621121081. The reversal of 1621121040 is 401211261.

1621121040 is a `hidden beast` number, since 1 + 621 + 1 + 2 + 1 + 0 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (840).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 167 ways as a sum of consecutive naturals, for example, 85322151 + ... + 85322169.

Almost surely, 2^1621121040 is an apocalyptic number.

1621121040 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 1621121040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3717913824).

1621121040 is an abundant number, since it is smaller than the sum of its proper divisors (5814706608).

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

1621121040 is a wasteful number, since it uses less digits than its factorization.

1621121040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 1621121040 is about 40263.1474179553. The cubic root of 1621121040 is about 1174.7311387258.

The spelling of 1621121040 in words is "one billion, six hundred twenty-one million, one hundred twenty-one thousand, forty".