42121440 has 72 divisors (see below), whose sum is σ = 143744328. Its totient is φ = 11232000.

The previous prime is 42121399. The next prime is 42121459. The reversal of 42121440 is 4412124.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13186 + ... + 16065.

It is an arithmetic number, because the mean of its divisors is an integer number (1996449).

Almost surely, 2^42121440 is an apocalyptic number.

42121440 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

42121440 is an abundant number, since it is smaller than the sum of its proper divisors (101622888).

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

42121440 is a wasteful number, since it uses less digits than its factorization.

42121440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29272 (or 29261 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 42121440 is about 6490.1032349262. The cubic root of 42121440 is about 347.9373648667.

Adding to 42121440 its reverse (4412124), we get a palindrome (46533564).

The spelling of 42121440 in words is "forty-two million, one hundred twenty-one thousand, four hundred forty".