21140657 has 8 divisors (see below), whose sum is σ = 22113600. Its totient is φ = 20172240.

The previous prime is 21140633. The next prime is 21140663. The reversal of 21140657 is 75604112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21140657 - 2¹⁴ = 21124273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21140677) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11594 + ... + 13292.

It is an arithmetic number, because the mean of its divisors is an integer number (2764200).

Almost surely, 2^21140657 is an apocalyptic number.

It is an amenable number.

21140657 is a deficient number, since it is larger than the sum of its proper divisors (972943).

21140657 is a wasteful number, since it uses less digits than its factorization.

21140657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2263.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21140657 is about 4597.8970192904. The cubic root of 21140657 is about 276.5070189089.

Adding to 21140657 its reverse (75604112), we get a palindrome (96744769).

The spelling of 21140657 in words is "twenty-one million, one hundred forty thousand, six hundred fifty-seven".