20157440 has 88 divisors (see below), whose sum is σ = 50307072. Its totient is φ = 7741440.

The previous prime is 20157433. The next prime is 20157451. The reversal of 20157440 is 4475102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158657 + ... + 158783.

Almost surely, 2^20157440 is an apocalyptic number.

20157440 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 20157440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25153536).

20157440 is an abundant number, since it is smaller than the sum of its proper divisors (30149632).

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

20157440 is a wasteful number, since it uses less digits than its factorization.

20157440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 20157440 is about 4489.7037764200. The cubic root of 20157440 is about 272.1521639945.

The spelling of 20157440 in words is "twenty million, one hundred fifty-seven thousand, four hundred forty".